Axially nested slide and lock expandable device

ABSTRACT

The invention relates generally to expandable medical implants for maintaining support of a body lumen and, in particular, to an axially nested, diametrically expandable, slide and lock vascular device for enlarging an occluded portion of a vessel. The axially nested vascular device desirably achieves both competitive crossing profiles while maintaining other key features, such as, for example, radial strength and luminal patency. The collapsed profile can also be made very thin without compromising radial strength. Thus, the vascular device can advantageously be deployed in small and difficult to reach areas or vessels. The axial nesting substantially eliminates radial overlap between mating structural elements thereby desirably allowing for a low, uniform profile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 11/196,800, filed Aug. 2, 2005 now U.S. Pat. No. 7,914,574, titled “AXIALLY NESTED SLIDE AND LOCK EXPANDABLE DEVICE,” the entirety of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to expandable medical implants for maintaining support of a body lumen. More particularly, the invention relates to a predominantly axially nested, diametrically expandable, slide and lock device for enlarging a portion of a body lumen.

2. Description of the Related Art

Stents or expandable stent grafts are implanted in a variety of body lumens in an effort to maintain their patency. The body lumens no matter how large or small may be vascular and nonvascular. These devices are typically intraluminally implanted by use of a catheter, which is inserted at an easily accessible location and then advanced to the deployment site. The stent is initially in a radially compressed or collapsed state to enable it to be maneuvered through the lumen. Once in position, the stent is deployed which, depending on its configuration, may be achieved either automatically or manually, by for example, the inflation of a balloon about which the stent is carried on the catheter.

An important and frequent use of stents is the treatment of blood vessels in situations where part of the vessel wall or stenotic plaque blocks or occludes fluid flow in the vessel. Often, a balloon catheter is utilized in a percutaneous transluminal coronary angioplasty procedure to enlarge the occluded portion of the vessel. However, the dilation of the occlusion can cause fissuring of atherosclerotic plaque and damage to the endothelium and underlying smooth muscle cell layer, potentially leading to immediate problems from flap formation or perforations in the vessel wall, as well as long-term problems with restenosis of the dilated vessel. Implantation of stents can provide support for such problems and prevent re-closure of the vessel or provide patch repair for a perforated vessel. Further, the stent may overcome the tendency of diseased vessel walls to collapse, thereby maintaining a more normal flow of blood through that vessel. Stents are also now being used in other clinical conditions such as in patients with unstable vulnerable plaque lesions.

As stents are normally employed to hold open an otherwise blocked, constricted or occluded lumen, a stent must exhibit sufficient radial or hoop strength in its expanded state to effectively counter the anticipated forces. It is, however, simultaneously necessary for the stent to be as compact as possible in its collapsed state in order to facilitate its advancement through the lumen. As a result, it is advantageous for a stent to have as large an expansion ratio as possible.

An additional consideration is the longitudinal flexibility of the device. Such characteristic is important not only in maneuvering the stent into position, which may require the traversal of substantial convolutions of the vasculature, but also to better conform to any curvature of the vasculature at the deployment site. At the same time it is, however, necessary for the stent to nonetheless exhibit sufficient radial strength to provide the necessary support for the lumen walls upon deployment.

Another problem inherent in many prior art stent configurations is the longitudinal contraction that such structures typically undergo as they are radially expanded. This not only reduces the effective length of the stent in its deployed state but may cause abrasion trauma to be inflicted on the vessel walls during expansion.

A number of very different approaches have been previously devised in an effort to address these various requirements. A popular approach calls for the stent to be constructed wholly of wire. The wire is bent, woven and/or coiled to define a generally cylindrical structure in a configuration that has the ability to undergo radial expansion. The use of wire has a number of disadvantages associated therewith including for example, its substantially constant cross-section which may cause greater or lesser than an ideal amount of material to be concentrated at certain locations along the stent. Additionally, wire has limitations with respect to the shapes it can be formed into thus limiting the expansion ratio, coverage area, flexibility and strength that can ultimately be attained therewith.

As an alternative to wire-based structures, stents have been constructed from tube stock. By selectively removing material from such tubular starting material, a desired degree of flexibility and expandability can be imparted to the structure. Etching techniques as well as laser-cutting processes are utilized to remove material from the tube. Laser cutting provides for a high degree of precision and accuracy with which very well defined patterns of material can be removed from the tube to conversely leave very precisely and accurately defined patterns of material in tact. The performance of such stent is very much a function of the pattern of material which remains (i.e., design) and material thickness. The selection of a particular pattern has a profound effect on the coverage area, expansion ratio and strength of the resulting stent as well as its longitudinal flexibility and longitudinal dimensional stability during expansion.

While the tube-based stents offer many advantages over the wire-based designs, it is nonetheless desirable to improve upon such designs in an effort to further enhance longitudinal flexibility and longitudinal dimensional stability during radial expansion without sacrificing radial hoop strength.

One stent design described by Fordenbacher, see e.g., U.S. Pat. Nos. 5,549,662 and 5,733,328, employs a plurality of elongated parallel stent components, each having a longitudinal backbone that spans the entire axial length of the stent and a plurality of opposing circumferential elements or fingers extending therefrom. The circumferential elements from one stent component weave into paired slots in the longitudinal backbone of an adjacent stent component. This weave-like interlocking configuration, wherein a circumferential element passes through the first slot in a pair and then weaves back through the second slot in the pair, is essential to Fordenbacher's goal of permitting radial expansion without material deformation. In addition, sufficient members of circumferential elements in the Fordenbacher stent may provide adequate scaffolding. Unfortunately, the circumferential elements have free ends, protruding from the paired slots. Moreover, the circumferential elements weaving through the paired slots also necessarily stand off from the lumen wall. Both the free ends and the stand off may pose significant risks of thrombosis and/or restenosis. Moreover, this stent design would tend to be rather inflexible as a result of the plurality of longitudinal backbones.

Some stents employ “jelly roll” designs, wherein a sheet is rolled upon itself with a high degree of overlap in the collapsed state and a decreasing overlap as the stent unrolls to an expanded state. Examples of such designs are described in U.S. Pat. No. 5,421,955 to Lau, U.S. Pat. Nos. 5,441,515 and 5,618,299 to Khosravi, and U.S. Pat. No. 5,443,500 to Sigwart. The disadvantage of these designs is that they tend to exhibit very poor longitudinal flexibility. In a modified design that exhibits improved longitudinal flexibility, multiple short rolls are coupled longitudinally. See e.g., U.S. Pat. No. 5,649,977 to Campbell and U.S. Pat. Nos. 5,643,314 and 5,735,872 to Carpenter. However, these coupled rolls lack vessel support between adjacent rolls. Furthermore, these designs exhibit extensive overlapping of stent elements in multiple layers, which makes the delivery profile rather thick.

Various types of stents, including those referenced above, are often described based on their means for expansion. For additional information, a variety of stents types are described by Balcon et al., “Recommendations on Stent Manufacture, Implantation and Utilization,” European Heart Journal (1997), vol. 18, pages 1536-1547, and Phillips, et al., “The Stenter's Notebook,” Physician's Press (1998), Birmingham, Mich.

Balloon expandable stents are manufactured in the collapsed condition and are expanded to a desired diameter with a balloon. The expandable stent structure may be held in the expanded condition by mechanical deformation of the stent as taught in, for example, U.S. Pat. No. 4,733,665 to Palmaz. Alternatively, balloon expandable stents may be held in the expanded condition by engagement of the stent walls with respect to one another as disclosed in, for example, U.S. Pat. No. 4,740,207 to Kreamer, U.S. Pat. No. 4,877,030 to Beck et al., and U.S. Pat. No. 5,007,926 to Derbyshire. Further still, the stent may be held in the expanded condition by one-way engagement of the stent walls together with tissue growth into the stent, as disclosed in U.S. Pat. No. 5,059,211 to Stack et al.

Although balloon expandable stents are the first stent type to be widely used in clinical applications, it is well recognized that balloon expandable stents have a variety of shortcomings which may limit their effectiveness in many important applications. For example, balloon expandable stents often exhibit substantial recoil (i.e., a reduction in diameter) immediately following deflation of the inflatable balloon. Accordingly, it may be necessary to over-inflate the balloon during deployment of the stent to compensate for the subsequent recoil. This is disadvantageous because it has been found that over-inflation may damage the blood vessel. Furthermore, a deployed balloon expandable stent may exhibit chronic recoil over time, thereby reducing the patency of the lumen. Still further, balloon expandable stents often exhibit foreshortening (i.e., a reduction in length) during expansion, thereby creating undesirable stresses along the vessel wall and making stent placement less precise. Still further, many balloon expandable stents, such as the original Palmaz-Schatz stent and later variations, are configured with an expandable mesh having relatively jagged terminal prongs, which increases the risk of injury to the vessel, thrombosis and/or restenosis.

Self-expanding stents are manufactured with a diameter approximately equal to, or larger than, the vessel diameter and are collapsed and constrained at a smaller diameter for delivery to the treatment site. Self-expanding stents are commonly placed within a sheath or sleeve to constrain the stent in the collapsed condition during delivery. After the treatment site is reached, the constraint mechanism is removed and the stent self-expands to the expanded condition. Most commonly, self-expanding stents are made of Nitinol or other shape memory alloy. One of the first self-expanding stents used clinically is the braided “WallStent,” as described in U.S. Pat. No. 4,954,126 to Wallsten. Another example of a self-expanding stent is disclosed in U.S. Pat. No. 5,192,307 to Wall wherein a stent-like prosthesis is formed of plastic or sheet metal that is expandable or contractible for placement.

Heat expandable stents are similar in nature to self-expanding stents. However, this type of stent utilizes the application of heat to produce expansion of the stent structure. Stents of this type may be formed of a shape memory alloy, such as Nitinol or other materials, such as polymers, that must go through a thermal transition to achieve a dimensional change. Heat expandable stents are often delivered to the affected area on a catheter capable of receiving a heated fluid. Heated saline or other fluid may be passed through the portion of the catheter on which the stent is located, thereby transferring heat to the stent and causing the stent to expand. However, heat expandable stents have not gained widespread popularity due to the complexity of the devices, unreliable expansion properties and difficulties in maintaining the stent in its expanded state. Still further, it has been found that the application of heat during stent deployment may damage the blood vessel.

In summary, although a wide variety of stents have been proposed over the years for maintaining the patency of a body lumen, none of the existing schemes has been capable of overcoming most or all of the above described shortcomings. As a result, clinicians are forced to weigh advantages against shortcomings when selecting a stent type to use in a particular application. Accordingly, there remains a need for an improved stent: one that is compact and flexible enough when collapsed to permit uncomplicated delivery to the affected area; one that is sufficiently flexible upon deployment to conform to the shape of the affected body lumen; one that expands uniformly to a desired diameter, without change in length; one that maintains the expanded size, without significant recoil; and one that has sufficient scaffolding to provide a clear through-lumen.

SUMMARY OF THE INVENTION

For purposes of summarizing the invention, certain aspects, advantages and novel features of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught or suggested herein without necessarily achieving other advantages as may be taught or suggested herein.

Some embodiments provide a diametrically expanding, slide and lock vascular device, prosthesis or stent comprising elements or members that do not substantially overlap each other in the radial direction, i.e., do not lay (nest) upon each other in the deployed state. In the nested (non-expanded, undeployed, predilated) position, the radial thickness of two overlapping elements is less than about two times the nominal material thickness. Overlap in the non-deployed state is generally acceptable as long a suitable crossing profile is achieved while in the deployed state there is desirably substantially no, minimal or reduced overlap.

During manufacture and assembly of the axially nested embodiments, the device structural elements are substantially majorly or primarily positioned side by side (axially) in the predilated or non-expanded state to substantially reduce or minimize the device crossing profile and bulk in both the undeployed (non-expanded, predilated) and deployed (expanded, dilated) states. Advantageously, by substantially reducing or eliminating the excess bulk typically encountered with a radially nesting device design, embodiments of the invention can be used to achieve competitive devices and crossing profiles with a wide variety of materials at a wide variety of thicknesses, thereby desirably allowing for optimum device design and performance.

Many conventional slide and lock vascular devices comprise elements that overlap each other in the radial direction, i.e., lay upon each other. This feature can limit that thickness of material that can be employed as well as the number of elements that can be employed. As the thickness or element number increases, competitive features of the device may be compromised, such as crossing profile. To provide acceptable crossing profiles, the thicknesses and the number of elements employed in these radially nesting devices is often reduced, which can have an impact on such features as reliability and device radial strength.

Embodiments of the invention provide an axially nested vascular device to achieve both competitive crossing profiles while maintaining other key features, such as, for example, radial strength and luminal patency. Advantageously, an axially nested device design allows for use of thicker materials to maintain radial strength, as needed or desired.

Embodiments of the invention can utilize a number of features to create slide and lock mechanisms that allow for controlled and predictable device expansion. For example, deflectable and non-deflectable elements and members can be employed to achieve desired deployment and lock out performance. The skilled artisan will appreciate that a variety of mechanisms, features and/or geometries can readily be included to achieve the desired deployment and lock out performance. For example, mechanisms can be employed that incorporate the bulk of the structural element, or smaller localized sub-elements can be employed.

Some embodiments provide a slide-and-lock stent that comprises a tubular member that is expandable from a collapsed state to an expanded state. The tubular member comprises at least one slide-and-lock section, comprising separate first and second axially nested, slidably coupled structural elements, at least one of which comprises a deflectable structure configured to deflect during expansion from the collapsed state to the expanded state, thereby resisting recoil, and wherein no portion of either structural elements weaves through paired slots in the other structural element.

In preferred variations, the deflectable structure is configured to deflect axially. Alternatively, the deflectable structure is configured to deflect radially.

Some embodiments provide a slide-and-lock stent that comprises a tubular member. The tubular member is expandable from a collapsed diameter to an expanded diameter. The tubular member comprises a first circumferential slide-and-lock section and a second circumferential slide-and-lock section. The slide-and-lock sections are longitudinally arranged and linked. Each of the slide-and-lock sections comprises a first axial element and a second axial element. The corresponding axial elements of each slide-and-lock section are spatially offset and connected by an interlocking articulating mechanism. Each of the first axial elements comprises a first rib with least one axially outwardly extending tooth and each of the second axial elements comprises a second rib with at least one axially inwardly extending tooth. Corresponding outwardly and inwardly extending teeth engage one another during expansion and are configured to permit one-way sliding between the corresponding first and second axial elements such that at least one of the corresponding first and second ribs is axially and temporarily deflected during expansion from the collapsed diameter to the expanded diameter.

Some embodiments provide a slide-and-lock stent that comprises a tubular member. The tubular member is expandable from a first diameter to a second diameter. The tubular member comprises a first circumferential section and a second circumferential section. The circumferential sections are longitudinally arranged. A linkage section connects the circumferential sections and is configured to provide flexibility. Each of the circumferential sections comprises a first slide-and-lock element and a second slide-and-lock element. The corresponding slide-and-lock elements of each circumferential section are radially connected by a slidable articulating mechanism. Each of the first slide-and-lock elements comprises at least one tooth and each of the second slide-and-lock elements comprises at least one radially extending tooth. During expansion the teeth of the first slide-and-lock elements engage corresponding radially extending teeth of the second slide and lock sections. The teeth are configured to permit one-way sliding between the corresponding first and second slide-and-lock elements such that at least a portion of the corresponding first and second slide-and-lock elements is radially deflected during expansion from the first diameter to the second diameter.

Some embodiments provide a slide-and-lock stent that comprises a tubular member. The tubular member is expandable from a collapsed state to an expanded state and comprises a lumen. The tubular member comprises at least one slide-and-lock section. The slide-and-lock section comprises at least one first structural element and at least one second structural element that are radially interlocked with an articulating mechanism such as to provide circumferential relative motion between the first structural element and the second structural element. The articulating mechanism is configured to permit one-way sliding between the first structural element and the second structural element such that at least a portion of the first structural element and/or at least a portion of the second structural element is elastically deflected during expansion from the collapsed state to the expanded state. Advantageously, the radial interlocking between the structural elements substantially eliminates radial overlap and allows for a substantially clear through-lumen such that substantially no structure protrudes into the lumen in either the collapsed or the expanded state.

In embodiments of the invention, structural elements can be linked together and interlocking elements captured through a wide variety of techniques. For example, channels can be created or added that allow the elements to slide within, between or therethrough. Other examples include, but are not limited to, capture straps, overhanging elements, covers, tongue-groove configurations and other suitable geometries, that can be employed or created through a wide variety of techniques to provide for linkage and capture of elements.

Embodiments of the invention provide an improved stent: one that desirably is small enough and flexible enough when collapsed to permit uncomplicated delivery to the affected area; one that is sufficiently flexible upon deployment to conform to the shape of the affected body lumen; one that expands uniformly to a desired diameter, without change in length; one that maintains the expanded size, without significant recoil; one that has sufficient scaffolding to provide a clear through-lumen; one that supports endothelialization or covering of the stent with vessel lining, which in turn minimizes the risk of thrombosis; and one that has a greater capacity to deliver therapeutic agents to minimize injury, treat restenosis and other vascular diseases.

Stents in accordance with embodiments of the invention can be fabricated or created using a wide variety of manufacturing methods, techniques and procedures. These include, but are not limited to, lasing, laser processing, milling, stamping, forming, casting, molding, laminating, bonding, welding, adhesively fixing, and the like, among others.

In some embodiments, stent features and mechanisms are created in a generally two dimensional geometry and further processed, for example by utilizing, but not limited to, bonding, lamination and the like, into three dimensional designs and features. In other embodiments, stent features and mechanisms are directly created into three dimensional shapes, for example by utilizing, but not limited to, processes such as injection molding and the like.

In preferred variations to the above-described stents, the stent further comprises a material selected from the group consisting of metal and polymer. Preferably, the polymer comprises a bioresorbable polymer. More preferably, the polymer comprises a radiopaque, bioresorbable polymer. In one aspect, the polymer forms a coating on at least a portion of the stent. The polymer coating may further comprise a biocompatible, bioresorbable polymer adapted to promote a selected biological response.

A method for re-treatment of a body lumen is disclosed in accordance with another embodiment of the present invention. The method comprises the steps of: deploying to a region of the body lumen any of the above described stents, wherein the stent is made from a bioresorbable polymer, and resides at the region for a period of time; and administering to the region, after the period of time, a second treatment, such as for example, treatments selected from the group consisting of a second stent of any kind, angioplasty, arthrectomy, surgical bypass, radiation, ablation, local drug infusion, etc., or any subsequent intervention or treatment.

In preferred variations to the above-described stents, the stent further comprises a therapeutic agent.

In preferred variations to the above-described stents, the stent further comprises a layered material. Preferably, the layered material comprises a bioresorbable polymer.

One key design aspect of embodiments of a slide and lock vascular device is its deployment ratio, that is, the ratio of final maximum diameter to initial compacted diameter. Depending upon the particular design being pursued or the application being addressed, the deployment ratio may vary. Advantageously, the stent of embodiments of the invention allows the number of elements to be increased or decreased, that is, varied, as needed or desired, to achieve optimization of the deployment ratio as well as device performance, crossing profile, flexibility, among others. This desirably adds to the device versatility and utility.

In preferred variations to the above-described stents, a cross-sectional geometry of at least a portion of the stent is tapered so as to produce generally desirable blood flow characteristics when the stent is placed in a blood vessel lumen.

In preferred variations to the above-described stents, the stent further comprises a retractable sheath sized for enclosing the tubular member during delivery to a treatment site.

In preferred variations to the above-described stents, the stent further comprises a solid wall region. The solid wall region may further comprise an opening.

In preferred variations to the above-described stents, the stent further comprises a polymeric sheath.

A system for treating a site within a vessel is also disclosed. The system comprises a catheter having a deployment means, and any of the above-described stents, wherein the catheter is adapted to deliver the stent to the site and the deployment means is adapted to deploy the stent. In preferred variations, the catheter is selected from the group consisting of over-the-wire catheters, coaxial rapid-exchange catheters, and multi-exchange delivery catheters.

All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus summarized the general nature of the invention and some of its features and advantages, certain preferred embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein having reference to the figures that follow, of which:

FIG. 1A is a simplified schematic end view of an axially nested slide and lock stent illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 1B is a simplified schematic side view of an axially nested slide and lock stent illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 2 is a simplified perspective view of an axially nested slide and lock stent in an expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 3 is a simplified partially exploded perspective view of an undeployed section of the stent of FIG. 2 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 4 is a simplified partially exploded perspective view of a deployed section of the stent of FIG. 2 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 5 is a simplified planar perspective view of sections of the stent of FIG. 2 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 6 is a simplified planar perspective partial view of a section of the stent of FIG. 2 with a capture mechanism illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 7 is a simplified planar perspective partial view of a section of the stent of FIG. 2 with a capture mechanism illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 8 is a simplified planar enlarged perspective view of the capture mechanism of FIG. 7.

FIG. 9 is a simplified planar perspective view of a stent articulation geometry illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 10 is a simplified planar perspective view of a stent articulation geometry illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 11 is a simplified planar perspective partial view of an axially nested slide and lock stent section with an axially deflecting arm mechanism illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 12 is a simplified planar perspective partial view of at least one axially nested slide and lock stent section with an axially deflecting arm mechanism illustrating features and advantages in accordance with another embodiment of the invention.

FIGS. 13A and 13B are simplified planar perspective partial views of axially nested slide and lock stent sections with an axially deflecting arm mechanism illustrating features and advantages in accordance with yet another embodiment of the invention.

FIGS. 14A and 14B are simplified planar perspective partial views of axially nested slide and lock stent sections with an axially deflecting mechanism illustrating features and advantages in accordance with still another embodiment of the invention.

FIG. 15 is a simplified planar perspective partial view of an axially nested slide and lock stent section with a radially deflecting arm mechanism illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 16 is a simplified planar perspective view of an axially nested slide and lock stent section with a radially deflecting arm mechanism illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 17 is simplified planar perspective enlarged partial view of the stent section of FIG. 16 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 18 is a simplified planar perspective enlarged partial view of the stent section of FIG. 16 showing radial rib deflection and illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 19 is a simplified planar perspective partial view of an axially nested slide and lock stent section with an axially deflecting mechanism in a collapsed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 20 is a simplified planar perspective partial view of the axially nested slide and lock stent section of FIG. 19 in an expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 21 is a conceptual simplified perspective view of an axially nested slide and lock stent in a deployed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 22 is a conceptual simplified perspective view of an axially nested slide and lock stent in an undeployed state illustrating features and advantages in accordance with an embodiment of the invention.

FIGS. 23A and 23B are conceptual simplified perspective views of an axially nested slide and lock stent in an undeployed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 24 is a simplified end view of the stent of FIG. 23B illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 25 is a conceptual simplified perspective view of the stent of FIG. 22 in a deployed state illustrating features and advantages in accordance with an embodiment of the invention.

FIGS. 26A and 26B are conceptual simplified perspective views of the respective stents of FIGS. 23A and 23B in a deployed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 27 is a simplified end view of the stent of FIG. 26B illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 28 is a simplified planar perspective view of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 29 is a simplified planar perspective view of an axially nested slide and lock stent in an almost fully expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 30 is a simplified planar view of an axially nested slide and lock stent in a collapsed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 31 is a simplified planar partial view of an axially nested slide and lock stent section in a collapsed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 32 is a simplified planar view of an axially nested slide and lock stent in a fully expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 33 is a simplified planar partial view of an axially nested slide and lock stent section a partially expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 34 is a simplified planar view of an axially nested slide and lock stent section in an almost fully expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 35 is a simplified planar partial view of an axially nested slide and lock stent section in an almost fully expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 36 is another simplified planar partial view of an axially nested slide and lock stent section in an almost fully expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 37 is a simplified planar perspective partial view of an axially nested slide and lock stent section in an almost fully expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 38 is a simplified planar perspective view of an axially nested slide and lock stent during its manufacture and assembly illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 39 is a simplified planar view of an axially nested slide and lock stent in a compacted state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 40 is a simplified planar view of the stent of FIG. 39 in an expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 41 is a simplified planar perspective partial view of the stent of FIG. 39 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 42 is a simplified planar perspective enlarged view of structural element of the stent of FIG. 39 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 43 is a simplified planar perspective view of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 44 is a simplified planar perspective view of an axially nested slide and lock stent in an expanded state illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 45 is a simplified planar enlarged perspective view of a slide and lock articulation mechanism of the stent of FIG. 44 illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 46 is a simplified planar perspective partial view of the stent of FIG. 43 or FIG. 44 during its manufacture and assembly illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 47 is a simplified planar perspective view of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 48 is a simplified planar perspective view of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 49 is a simplified planar perspective partial view of the stent of FIG. 47 during its manufacture and assembly illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 50 is a simplified planar perspective partial view of the stent of FIG. 47 during its manufacture and assembly illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 51 is a conceptual planar perspective view of structural elements of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 52 is a conceptual planar perspective view of structural elements of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with another embodiment of the invention.

FIG. 53 is a conceptual planar perspective view of structural elements of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with yet another embodiment of the invention.

FIG. 54 is a conceptual planar perspective view of structural elements of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with still another embodiment of the invention.

FIG. 55 is a conceptual planar perspective view of structural elements of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with a further embodiment of the invention.

FIG. 56 is a conceptual planar perspective view of structural elements of an axially nested slide and lock stent in a partially expanded state illustrating features and advantages in accordance with a another further embodiment of the invention.

FIG. 57 is a simplified planar perspective view of an axially nested slide and lock stent illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 58 is a simplified planar perspective view of the stent of FIG. 57 in a collapsed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 59 is a simplified planar view of the stent of FIG. 57 in a collapsed state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 60 is a simplified planar view of the stent of FIG. 57 in an expanded state illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 61 is a simplified planar perspective top view of a slide and lock articulation mechanism of the stent of FIG. 57 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 62 is a simplified planar perspective bottom view of a slide and lock articulation mechanism of the stent of FIG. 57 illustrating features and advantages in accordance with an embodiment of the invention.

FIG. 63 is a simplified planar perspective view of an axially nested slide and lock stent in an expanded state illustrating features and advantages in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the description sets forth various embodiment specific details, it will be appreciated that the description is illustrative only and should not be construed in any way as limiting the invention. Furthermore, various applications of the invention, and modifications thereto, which may occur to those who are skilled in the art, are also encompassed by the general concepts described herein.

The term “stent” is used herein to designate embodiments for placement in (1) vascular body lumens (i.e., arteries and/or veins) such as coronary vessels, neurovascular vessels and peripheral vessels for instance renal, iliac, femoral, popliteal, subclavian and carotid; and in (2) nonvascular body lumens such as those treated currently i.e., digestive lumens (e.g., gastrointestinal, duodenum and esophagus, biliary ducts), respiratory lumens (e.g., tracheal and bronchial), and urinary lumens (e.g., urethra); (3) additionally such embodiments may be useful in lumens of other body systems such as the reproductive, endocrine, hematopoietic and/or the integumentary, musculoskeletal/orthopedic and nervous systems (including auditory and ophthalmic applications); and, (4) finally, stent embodiments may be useful for expanding an obstructed lumen and for inducing an obstruction (e.g., as in the case of aneurysms).

In the following description of the present invention, the term “stent” may be used interchangeably with the term “prosthesis” and should be interpreted broadly to include a wide variety of devices configured for supporting a segment of a body passageway. Furthermore, it should be understood that the term “body passageway” encompasses any lumen or duct within a body, such as those described herein.

Still further, it should be understood that the term “shape-memory material” is a broad term that includes a variety of known shape memory alloys, such as nickel-titanium alloys, as well as any other materials that return to a previously defined shape after undergoing substantial plastic deformation.

In one preferred embodiment, the assembled stent generally comprises a tubular member having a length in the longitudinal axis and a diameter in the circumferential axis sized for insertion into the body lumen. The tubular member is preferably formed with a “clear through-lumen,” which is defined as having little or no structure protruding into the lumen in either the collapsed or expanded condition.

In many of the embodiments illustrated and described herein, the intraluminal stent is preferably provided with “slide-and-lock elements” generally referred to herein as “axial elements.” The axial elements are slidably interconnected with circumferentially adjacent axial elements in a manner wherein the stent exhibits mono-directional axial expansion from an axially collapsed state to an axially expanded state, e.g., during deployment. The axial elements are preferably configured to provide a ratcheting effect such that the stent is maintained (i.e., “locked-out”) in the expanded diameter after deployment within the body passage. More particularly, the structures (e.g., axial elements) may flex or bend; however, unlike conventional balloon expandable stents, no substantial plastic deformation of the elements are required during expansion of the stent from a collapsed diameter to an expanded diameter. Elements of this type are generally referred to herein as “non-deforming elements.” Accordingly, the term “non-deforming element” is intended to generally describe a structure that substantially maintains its original dimensions (i.e., length and width) during deployment of the stent. Each axial element is preferably formed as a flat sheet that is cut or otherwise shaped to provide a slide-and-lock mechanism.

The phrase “weaves through paired slots” has the meaning described in U.S. Pat. Nos. 5,549,662 and 5,733,328. As used herein, this phrase describes a particular slidable coupling or articulation between stent components, wherein a portion of one stent component passes through one of a pair of slots in another stent component, and then passes back through the second of the pair of slots, creating a weave-like interlocking configuration. Preferred embodiments of the present invention employ slidable couplings or articulations between stent components that avoid weave-like configurations, such that in these preferred embodiments, no portion of a stent component weaves through paired slots in another stent component.

The term “radial strength,” as used herein, describes the external pressure that a stent is able to withstand without incurring clinically significant damage. Due to their high radial strength, balloon expandable stents are commonly used in the coronary arteries to ensure patency of the vessel. During deployment in a body lumen, the inflation of the balloon can be regulated for expanding the stent to a particular desired diameter. Accordingly, balloon expandable stents may be used in applications wherein precise placement and sizing are important. Balloon expandable stents may be used for direct stenting applications, where there is no pre-dilation of the vessel before stent deployment, or in prosthetic applications, following a pre-dilation procedure (e.g., balloon angioplasty). During direct stenting, the expansion of the inflatable balloon dilates the vessel while also expanding the stent.

In another preferred embodiment, the stent further comprises a tubular member formed from a biocompatible and preferably, bioresorbable polymer, such as those disclosed in co-pending U.S. application Ser. No. 10/952,202; incorporated herein in its entirety by reference. It is also understood that the various polymer formulae employed may include homopolymers and heteropolymers, which includes stereoisomers. Homopolymer is used herein to designate a polymer comprised of all the same type of monomers. Heteropolymer is used herein to designate a polymer comprised of two or more different types of monomer which is also called a co-polymer. A heteropolymer or co-polymer may be of a kind known as block, random and alternating. Further with respect to the presentation of the various polymer formulae, products according to embodiments of the present invention may be comprised of a homopolymer, heteropolymer and/or a blend of such polymers.

The term “bioresorbable” is used herein to designate polymers that undergo biodegradation (through the action of water and/or enzymes to be chemically degraded) and at least some of the degradation products are eliminated and/or absorbed by the body. The term “radiopaque” is used herein to designate an object or material comprising the object visible by in vivo analysis techniques for imaging such as, but not limited to, methods such as x-ray radiography, fluoroscopy, other forms of radiation, MRI, electromagnetic energy, structural imaging (such as computed or computerized tomography), and functional imaging (such as ultrasonography). The term, “inherently radiopaque”, is used herein to designate polymer that is intrinsically radiopaque due to the covalent bonding of halogen species to the polymer. Accordingly, the term does encompass a polymer which is simply blended with a halogenated species or other radiopacifying agents such as metals and their complexes.

In another preferred variation, the stent further comprises an amount of a therapeutic agent (for example, a pharmaceutical agent and/or a biologic agent) sufficient to exert a selected therapeutic effect. The term “pharmaceutical agent”, as used herein, encompasses a substance intended for mitigation, treatment, or prevention of disease that stimulates a specific physiologic (metabolic) response. The term “biological agent”, as used herein, encompasses any substance that possesses structural and/or functional activity in a biological system, including without limitation, organ, tissue or cell based derivatives, cells, viruses, vectors, nucleic acids (animal, plant, microbial, and viral) that are natural and recombinant and synthetic in origin and of any sequence and size, antibodies, polynucleotides, oligonucleotides, cDNA's, oncogenes, proteins, peptides, amino acids, lipoproteins, glycoproteins, lipids, carbohydrates, polysaccharides, lipids, liposomes, or other cellular components or organelles for instance receptors and ligands. Further the term “biological agent”, as used herein, includes virus, serum, toxin, antitoxin, vaccine, blood, blood component or derivative, allergenic product, or analogous product, or arsphenamine or its derivatives (or any trivalent organic arsenic compound) applicable to the prevention, treatment, or cure of diseases or injuries of man (per Section 351(a) of the Public Health Service Act (42 U.S.C. 262(a)). Further the term “biological agent” may include 1) “biomolecule”, as used herein, encompassing a biologically active peptide, protein, carbohydrate, vitamin, lipid, or nucleic acid produced by and purified from naturally occurring or recombinant organisms, tissues or cell lines or synthetic analogs of such molecules, including antibodies, growth factors, interleukins and interferons; 2) “genetic material” as used herein, encompassing nucleic acid (either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), genetic element, gene, factor, allele, operon, structural gene, regulator gene, operator gene, gene complement, genome, genetic code, codon, anticodon, messenger RNA (mRNA), transfer RNA (tRNA), ribosomal extrachromosomal genetic element, plasmagene, plasmid, transposon, gene mutation, gene sequence, exon, intron, and, 3) “processed biologics”, as used herein, such as cells, tissues or organs that have undergone manipulation. The therapeutic agent may also include vitamin or mineral substances or other natural elements.

In some embodiments, the design features of the axial elements can be varied to customize the functional features of strength, compliance, radius of curvature at deployment and expansion ratio. In some embodiments, the stent comprises a resorbable material and vanishes when its job is done. In some embodiments, the stent serves as a therapeutic delivery platform.

The stent preferably comprises at least one longitudinal module, which consists of a series of axial elements, including one or more slide-and-lock axial elements and optionally one or more passive axial elements, linked in the longitudinal axis by flexible coupling portions. Preferably, the axial elements from two or more similar longitudinal modules are slidably connected to circumferentially adjacent axial elements. Of course, single module (or jellyroll-type) embodiments are also encompassed within the scope of the present disclosure. Each module is preferably a discrete, unitary structure that does not stretch or otherwise exhibit any substantial permanent deformation during stent deployment.

Some embodiments relate to an axially expandable stent used to open, or to expand a targeted area in a body lumen. In some embodiments, the assembled stent comprises a tubular member having a length in the longitudinal axis and a diameter in the circumferential or axial axis, of appropriate size to be inserted into the body lumen. The length and diameter of the tubular member may vary considerably for deployment in different selected target lumens depending on the number and configuration of the structural components, described below. The tubular member is adjustable from at least a first collapsed diameter to at least a second expanded diameter. One or more stops and engaging elements or tabs are incorporated into the structural components of the tubular member whereby recoil (i.e., collapse from an expanded diameter to a more collapsed diameter) is minimized to less than about 5%.

The tubular member in accordance with some embodiments has a “clear through-lumen,” which is defined as having no structural elements protruding into the lumen in either the collapsed or expanded diameters. Further, the tubular member has smooth marginal edges to minimize the trauma of edge effects. The tubular member is preferably thin-walled (wall thickness depending on the selected materials ranging from less than about 0.010 inches for plastic and degradable materials to less than about 0.002 inches for metal materials) and flexible (e.g., less than about 0.01 Newtons force/millimeter deflection) to facilitate delivery to small vessels and through tortuous vasculature.

Stents according to aspects of the present invention are preferably formed with walls for providing a low crossing profile and for allowing excellent longitudinal flexibility. In preferred embodiments, the wall thickness is about 0.0001 inches to about 0.0250 inches, and more preferably about 0.0010 to about 0.0100 inches. However, the wall thickness depends, at least in part, on the selected material. For example, the thickness may be less than about 0.0080 inches for plastic and degradable materials and may be less than about 0.0020 inches for metal materials. More particularly, for a 3.00 mm stent application, when a plastic material is used, the thickness is preferably in the range of about 0.0040 inches to about 0.0085 inches. However, a stent having various diameters may employ different thicknesses for biliary and other peripheral vascular applications. The above thickness ranges have been found to provide preferred characteristics through all aspects of the device including assembly and deployment. However, it will be appreciated that the above thickness ranges should not be limiting with respect to the scope of the invention and that the teachings of the present invention may be applied to devices having dimensions not discussed herein.

Some aspects are also disclosed in co-pending U.S. patent application Ser. Nos. 11/016,269, 60/601,526, 10/655,338, 10/773,756, 10/897,235; each of which is incorporated herein in its entirety by reference thereto.

The preferred embodiments of the invention described herein relate generally to expandable medical implants for maintaining support of a body lumen and, in particular, to an axially nested, diametrically expandable, slide and lock vascular device for enlarging an occluded portion of a vessel.

While the description sets forth various embodiment specific details, it will be appreciated that the description is illustrative only and should not be construed in any way as limiting the invention. Furthermore, various applications of the invention, and modifications thereto, which may occur to those who are skilled in the art, are also encompassed by the general concepts described herein.

Some embodiments relate to an expandable stent having a plurality of longitudinally arranged sections, segments or frames. The sections have a plurality of axially nesting sliding and locking elements permitting one-way sliding of the elements from a collapsed diameter to an expanded/deployed diameter, but inhibiting recoil from the expanded diameter. In some embodiments, the stent comprises a polymer and is fabricated by a combination of laminating and laser cutting a plurality of layers. Advantageously, the stent substantially reduces or minimizes overlap between the structural elements and thus desirably reduces the effective wall thickness of the stent. Another advantage is that the stent design elements and interlocks can be varied to customize the functional features of strength, compliance, radius of curvature at deployment and expansion ratio. In some embodiments, the stent comprises a resorbable material and vanishes when its job is done. In some embodiments, the stent serves as a delivery platform for therapeutic agents such as pharmaceutical compounds or biological materials.

Some embodiments relate to a radially expandable stent used to open, or to expand a targeted area in a body lumen. Some embodiments relate to a radially expandable stent used as a drug delivery platform to treat vascular conditions. In some embodiments, the assembled stent comprises a tubular member having a length in the longitudinal axis and a diameter in the radial axis, of appropriate size to be inserted into the body lumen. The length and diameter of the tubular member may vary considerably for deployment in different selected target lumens depending on the number and configuration of the structural components, described below. The tubular member is adjustable from at least a first collapsed diameter to at least a second expanded diameter. One or more stops, teeth, slots or grooves and engaging elements, tabs, teeth or tongues are incorporated into the structural components of the tubular member whereby recoil (i.e., collapse from an expanded diameter to a more collapsed diameter) is minimized to less than about 5%.

The tubular member in accordance with some embodiments has a “clear through-lumen,” which is defined as having no structural elements protruding into the lumen in either the collapsed or expanded diameters. Further, the tubular member has smooth marginal edges to minimize the trauma of edge effects. The tubular member is preferably thin-walled (wall thickness depending on the selected materials and intended vessel size to be treated ranging from less than about 0.009 inches for plastic and resorbable materials to less than about 0.0008 inches for metal materials) and flexible to facilitate delivery to small vessels and through tortuous vasculature. The thin walled design can also minimize blood turbulence and thus risk of thrombosis. The thin profile of the deployed tubular member in accordance with some embodiments also facilitates more rapid endothelialization of the stent.

In some embodiments, the wall of the tubular member comprises at least one section, which comprises at least one sliding and locking structural element. Preferably, a plurality of sections are connected in the longitudinal axis via linkage elements which couple at least some of the structural elements between adjacent sections. The structural elements are configured within each section so as to generally define the circumference of the tubular member. In some embodiments, each structural element within a section is a discrete, unitary structure. In some embodiments, the tubular member comprises an integral unit including one or more sections with one or more structural elements. In one embodiment, each structural element comprises one or more circumferential ribs bowed in the radial axis to form a fraction of the total circumference of the tubular member.

At least some of the structural elements have at least one articulating mechanism (e.g., deflecting or non-deflecting) for providing slidable engagement between adjacent circumferentially offset structural elements and/or adjacent axially offset structural elements. In one embodiment, the articulating mechanism includes a tongue and groove configuration. The articulating between structural elements is such that a locking or ratcheting mechanism is formed, whereby the adjacent elements may slide circumferentially in one direction but are substantially prevented from sliding circumferentially in an opposite direction. Accordingly, the tubular member may be radially expanded from a smaller diameter to a larger diameter, but advantageously recoil to a smaller diameter is minimized by the locking mechanism. The amount of recoil can be customized for the application by adjusting the configuration of the articulating locking mechanism. In one embodiment, the recoil is less than about 5%.

Some features and arrangements of embodiments of stents are disclosed in U.S. Pat. Nos. 6,033,436, 6,224,626 and 6,623,521 each issued to Steinke, the disclosures of each one of which are hereby incorporated in their entirety by reference thereto.

Embodiments and Design Features of the Device

FIG. 1A schematically depicts an end view of one embodiment of a vascular device, prosthesis or stent 10′ generally comprising one or more longitudinally arranged sections, segments or frames 12′. Each section 12′ includes two or more structural elements 14′ that are radially or circumferentially coupled to other structural elements 14′ of the same section 12′ by one-way slide and lock articulating mechanisms 16′.

The articulating mechanisms 16′ allow one-way expansion of the section 12′ from a first collapsed diameter to a second expanded diameter. During expansion, there is circumferential relative motion between the structural elements 14′ as generally shown by arrows 18′ such that one or both of the structural elements 14′ slidably move apart.

As described in more detail below, even though the structural elements 14′ of the same section 12′ are radially or circumferentially coupled, the sections 12′ and structural elements 14′ are designed and configured such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 14′ in both the non-expanded and expanded states. Thus, the structural elements 14′ are referred to as being axially, longitudinally or non-radially nested.

FIG. 1B schematically depicts a side view of another embodiment of a vascular device, prosthesis or stent 10″ generally comprising two or more longitudinally arranged sections, segments or frames 12″. Each section 12″ includes one or more structural elements 14″. Structural elements 14″ of adjacent sections 12″ are axially or longitudinally coupled to one another by one-way slide and lock articulating mechanisms 16″.

The articulating mechanisms 16″ allow one-way expansion of the sections 12″ from a first collapsed diameter to a second expanded diameter. During expansion, there is circumferential relative motion between the structural elements 14″ as generally shown by arrows 18″ such that one or both of the structural elements 14″ slidably move.

As described in more detail below, the axial or longitudinal coupling between the structural elements 14″ of adjacent sections 12″, and the design and configuration of the sections 12″ and structural elements 14″ are such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 14″ in both the non-expanded and expanded states. Thus, the structural elements 14″ are referred to as being axially, longitudinally or non-radially nested.

Advantageously, the axially nested embodiments of FIGS. 1A and 1B, and others as described, taught or suggested herein, allow suitable crossing profiles (e.g. luminal size) while maintaining desirable radial strength and luminal patency. In the non-expanded state, there is also minimal or reduced overlap between structural elements, so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device. The collapsed profile can also be made very thin without compromising radial strength. Thus, the stent of embodiments of the invention can be deployed in small and difficult to reach vessels, such as the intercranial vessels distal to the carotids and the remote coronary vessels.

The axially nested embodiments of FIGS. 1A and 1B, and others as described, taught or suggested herein advantageously significantly minimizes radial stacking (overlap) which results in less material thickness in the nondeployed and deployed configurations and thus desirably reduces the effective wall thickness of the deployed stent. Stated differently, the stent substantially eliminates radial overlap between mating structural elements thereby desirably allowing for a low, uniform profile.

FIG. 2 shows one embodiment of an axially nested slide and lock vascular device, prosthesis or stent 10 having a tubular form with a wall comprising a plurality of generally longitudinally arranged linked circumferential sections, segments or frames 12 a, 12 s. The stent 10 has a through lumen 20 which is expandable from a first diameter to a second diameter. The stent 10 and/or the lumen 20 have a generally longitudinal axis 24.

The stent 10 comprises alternatingly arranged slide and lock sections 12 a and linkage sections 12 s. Each section 12 a includes a pair of male structural elements 14 m 1, 14 m 2 and a pair of female structural elements 14 f 1, 14 f 2 that respectively slidingly mate via respective interlocking articulating mechanisms 16 mf 1, 16 mf 2. In modified embodiments, fewer or more structural elements may be efficaciously utilized, as needed or desired.

Each linkage section 12 s includes a pair of spring elements 22 s 1, 22 s 2 with the spring elements 22 s 1 connected to adjacent female structural elements 14 f 1, 14 f 2 and the spring elements 22 s 2 connected to adjacent male structural elements 14 m 1, 14 m 2. As described further below, the spring elements 22 can allow expansion of the sections 12 s and also allow for deflection of ribs of the structural elements 14 during stent expansion. The spring elements 22 also allow for flexibility in the non-deployed and deployed states. In modified embodiments, fewer or more spring elements may be efficaciously utilized, as needed or desired.

During stent expansion, there is circumferential relative motion between the mating male structural elements 14 m 1, 14 m 2 and female structural elements 14 f 1, 14 f 2 as generally shown by arrows 18. One or both of the mating male-female structural elements 14 m 1, 14 f 1 and 14 m 2, 14 f 2 may slidably move apart.

FIGS. 3 and 4 are partially exploded views of one of the sections 12 a. FIG. 3 shows the section 12 a in a collapsed or undeployed state and FIG. 4 shows the section 12 a in an expanded or deployed state.

The female structural element 14 f 1 generally comprises a pair of spaced ribs or arms 26 f 1 to form a gap 30 f 1 therebetween. Each of the ribs 26 f 1 includes an inwardly extending end stop, tooth or tab 32 f 1 that engage the male structural element 14 m 1.

The female structural element 14 f 2 generally comprises a pair of spaced ribs or arms 26 f 2 to form a gap 30 f 2 therebetween. Each of the ribs 26 f 2 includes an inwardly extending end stop, tooth or tab 32 f 2 that engage the male structural element 14 m 2.

The female structural elements 14 f 1, 14 f 2 share a common end portion 28 to which the ribs 26 f 1 and 26 f 2 are connected. In one embodiment, the female structural elements 14 f 1, 14 f 2 comprise an integral unit. In modified embodiments, the female structural elements 14 f 1, 14 f 2 can efficaciously be connected by other techniques, as needed or desired.

The male structural element 14 m 1 generally comprises a pair of spaced ribs or arms 36 m 1 to form a gap 40 m 1 therebetween. In the collapsed state (FIG. 3), the ribs 36 m 1 extend into the gap 30 f 1 between the female ribs 26 f 1. Each of the ribs 36 m 1 includes a plurality of outwardly extending spaced stops, teeth or tabs 42 m 1 that engage the female structural element 14 f 1 and its stops 32 f 1.

The male structural element 14 m 2 generally comprises a pair of spaced ribs or arms 36 m 2 to form a gap 40 m 2 therebetween. In the collapsed state (FIG. 3), the ribs 36 m 2 extend into the gap 30 f 2 between the female ribs 26 f 2. Each of the ribs 36 m 2 includes a plurality of outwardly extending spaced stops, teeth or tabs 42 m 2 that engage the female structural element 14 f 2 and its stops 32 f 2.

The male structural elements 14 m 1, 14 m 2 share a common end portion 38 to which the ribs 36 m 1 and 36 m 2 are connected. In one embodiment, the male structural elements 14 m 1, 14 m 2 comprise an integral unit. In modified embodiments, the male structural elements 14 m 1, 14 m 2 can efficaciously be connected by other techniques, as needed or desired.

During expansion, there is circumferential relative motion between the male set of ribs 36 m 1 and female set of ribs 26 f 1 with one or both of the sets slidably moving apart. Similarly, there is circumferential relative motion between the male set of ribs 36 m 2 and female set of ribs 26 f 2 with one or both of the sets slidably moving apart. The motion is generally denoted by arrows 18.

As illustrated by FIGS. 3 and 4, during expansion, the stops 32 f 1, 32 f 2 and the respective stops 42 m 1, 42 m 2 cross one another. This is accomplished by utilizing an axially deflecting mechanism. Thus, during “cross-over” the male ribs 36 m 1 and/or the female ribs 26 f 1 are respectively deflected outwards and inwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 44.

Similarly, during “cross-over” the male ribs 36 m 2 and/or the female ribs 26 f 2 are respectively deflected outwards and inwards and then resume their original undeflected position with their axial motion being generally denoted by the arrows 44. In one embodiment, the spring elements 22 s 1, 22 s 2 facilitate this rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

As indicated above, either the male ribs 36 m 1, 36 m 2, the female ribs 26 f 1, 26 f 2, both or any other suitable combination of ribs may axially deflect to achieve the desired expansion and other deployment characteristics. The axial deflection is caused by the generation of a generally axial or longitudinal force when the female stops 32 f 1, 32 f 2 and respective male stops 42 m 1, 42 m 2 slide over, engage or abut one another. As discussed further below, at full expansion, a capture mechanism is provided to limit further stent expansion.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 14 m 1, 14 m 2 and respective female structural elements 14 f 1, 14 f 2 in both the collapsed state (see, for example, FIG. 3) and the expanded state (see, for example, FIG. 4). The male ribs 36 m 1, 36 m 2 and respective female ribs 26 f 1, 26 f 2 of a given section 12 a are axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 14 are referred to as being axially nested since their radial overlap is substantially reduced or minimal.

FIG. 5 shows a planar view of the active slide and lock section 12 a connected to an adjacent linkage section 12 s. The linkage section 12 s includes three elements 22 s 1′, 22 s 1″ and 22 s 2 some or all of which may be spring elements.

In the embodiment of FIG. 5, two independent spring elements 22 s 1′, 22 s 1″ of the linkage section 12 s are connected to a respective one of the female structural elements 14 f 1, 14 f 2 and one spring element 22 s 2 of the same linkage section 12 s is connected to both the male structural elements 14 m 1, 14 m 2. In modified embodiments, any suitable number of spring elements 22 s and/or rigid elements may be connected to the male and female structural elements 14 m, 14 f with efficacy, as needed or desired, to control the rib deflection and stent deployment characteristics.

The female stops 32 f 1, 32 f 2 are configured so that they have generally flat respective end surfaces 46 f 1, 46 f 2 to substantially reduce or minimize recoil and generally tapered respective engaging surfaces 48 f 1, 48 f 2 to facilitate one-way sliding. Similarly, the male stops 42 m 1, 42 m 2 are configured so that they have generally flat respective end surfaces 50 m 1, 50 m 2 to substantially reduce or minimize recoil and generally tapered respective engaging surfaces 52 m 1, 52 m 2 to facilitate one-way sliding. Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

FIG. 6 shows one embodiment of the female structural element 14 f 1 including a capture mechanism, device or strap 54 f 1′ to provide profile capture, containment or control during stent expansion. A similar or other suitable capture mechanism can also be associated with the other female structural element 14 f 2.

The capture strap 54 f 1′ is connected to the female ribs 26 f 1 and extends therebetween. In one embodiment, the female structural element 14 f 1 including the capture strap 54 f 1′ comprise an integral unit. In modified embodiments, the capture strap, member or element 54 f 1′ can efficaciously be connected to the ribs 26 f 1 by other techniques, as needed or desired.

In the illustrated embodiment of FIG. 6, the capture strap 54 f 1′ is located substantially adjacent to the open end of the gap 30 f 1 formed between the female ribs 26 f 1 and substantially adjacent to the end stops 32 f 1. The capture strap 54 f 1′ permits sliding relative motion between itself (and hence the female structural element 14 f 1) and the male structural element 14 m 1 such that the male ribs 36 m 1 desirably do not jump out of their track during stent deployment.

The female end stops 32 f 1 and the male end stops 42 m 1′ are configured to provide engagement that stops further stent expansion. The end stops 42 m 1′ are located adjacent to the open end of the gap 40 m 1 formed between the ribs 36 m 1. Any one of a number of suitable locking or lock-out mechanisms may be utilized to control the maximum stent expansion such as tongue and groove arrangements and the like, among others.

FIGS. 7 and 8 show another embodiment of a capture mechanism, device or strap 54 f 1″ incorporated with the female structural element 14 f 1 to provide profile control in the non-deployed or collapsed state. A similar or other suitable capture mechanism can also be associated with the other female structural element 14 f 2. The capture strap 54 f 1″ may be used in conjunction with the capture strap 54 f 1′ (FIG. 6) or independently, as needed or desired.

The capture strap 54 f 1″ is connected to the female ribs 26 f 1 and extends therebetween. In one embodiment, the female structural element 14 f 1 including the capture strap 54 f 1″ comprise an integral unit. In modified embodiments, the capture strap 54 f 1″ can efficaciously be connected to the ribs 26 f 1 by other techniques, as needed or desired.

In the illustrated embodiment of FIGS. 7 and 8, the capture strap, member or element 54 f 1″ is located substantially adjacent to the closed end of the gap 30 f 1 formed between the female ribs 26 f 1 and substantially at the end portion 28. The capture strap 54 f 1″ holds the male ribs 36 f 1 in place in the deployed state and prevents them from jumping out. This desirably maintains the stent profile.

[0134] In the embodiment of FIGS. 7 and 8, the end portion capture strap 54 f 1″ includes a pair of spaced slots or grooves 56 f 1″ through which respective male ribs 36 m 1 extend. The slots 56 f 1″ are configured to allow slidable relative motion between the ribs 36 m 1 and slots 56 f 1″ thereby allowing the end stops 42 m 1″ to pass therethrough during stent expansion or deployment. Grooves or tracks may be provided on the inwardly facing surfaces of the female ribs 26 f 1 that engage the male stops 42 m 1, 42 m 1″ during stent expansion, thereby preventing the male ribs 36 m 1 from jumping out and disturbing the stent profile.

The female end stops 32 f 1 and the male end stops 42 m 1″ are configured to provide engagement that stops further stent expansion. The end stops 42 m 1″ are located adjacent to the open end of the gap 40 m 1 formed between the ribs 36 m 1. Any one of a number of suitable locking or lock-out mechanisms may be utilized to control the maximum stent expansion such as tongue and groove arrangements and the like, among others.

FIG. 9 shows an capture and/or articulation geometry between a male structural element 14 m 1′ and a female structural element 14 f 1′ that joins or links adjacent elements 14 m 1′, 14 f 1′ in accordance with one embodiment. Female rib 26 f 1′ includes a groove, slot, recess or track 58 f 1′ through which a portion, stops, teeth or tabs 42 m 1′ of a male rib 36 m 1′ slide during stent expansion. Advantageously, this prevents the male rib 36 m 1′ from jumping out of its track and disturbing the stent profile. The slide or expansion direction is generally denoted by arrows 18. The groove 58 f 1′ also keeps the male rib 36 m 1′ in place in the stent collapsed state.

FIG. 10 shows an capture and/or articulation geometry between a male structural element 14 m 1″ and a female structural element 14 f 1″ that joins or links adjacent elements 14 m 1″, 14 f 1″ in accordance with another embodiment. Female rib 26 f 1″ includes a groove, slot, recess or track 58 f 1″ through which a portion, stops, teeth or tabs 42 m 1″ of a male rib 36 m 1″ slide during stent expansion. Advantageously, this prevents the male rib 36 m 1″ from jumping out of its track and disturbing the stent profile. The slide or expansion direction is generally denoted by arrows 18. The groove 58 f 1″ also keeps the male rib 36 m 1″ in place in the stent collapsed state.

FIG. 11 shows a portion of an axially nested expandable stent section, segment or frame 112′ in accordance with one embodiment. The section 112′ generally comprises a male structural element 114 m′ and a female structural element 114 f′ radially or circumferentially coupled by a slide and lock articulating mechanism 116 mf′. During stent expansion, there is circumferential relative motion between the mating male structural element 114 m′ and female structural element 114 f′ as generally shown by arrows 118′. One or both of the mating male-female structural elements 114 m′ and 114 f′ may slidably move apart.

The female structural element 114 f′ generally comprises a pair of ribs or arms 126 f′ spaced by a gap 130 f′. In the collapsed state, at least a portion of the male structural element 114 m′ extends within the gap 130 f′. The male structural element 114 m′ generally comprises a pair of ribs or arms 136 m′ spaced by a gap 140 m′.

In the embodiment of FIG. 11, each of the female ribs 126 f′ includes a plurality of inwardly extending spaced stops, teeth or tabs 132 f′ that engage the male structural element 114 m′ and each of the male ribs 136 m′ includes an outwardly extending end stop, tooth or tab 142 m′ that engage the female structural element 114 f′ and its stops 132 f′. The stops 132 f′ and 142 m′ are configured to permit one-way slidable relative motion between the male and female structural elements 114 m′, 114 f′.

During stent expansion, the stops 132 f′ and the stops 142 m′ cross one another. This is accomplished by utilizing an axially deflecting mechanism. Thus, during “cross-over” the female ribs 126 f′ and/or the male ribs 136 m′ are respectively deflected outwards and inwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 144′. In one embodiment, spring elements facilitate this rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

As indicated above, either the female ribs 126 f′, the male ribs 136 m′, both or any other suitable combination of ribs may axially deflect to achieve the desired expansion and other deployment characteristics. The axial deflection is caused by the generation of a generally axial or longitudinal force when the female stops 132 f′ and respective male stops 142 m′ slide over, engage or abut one another. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 114 m′ and female structural elements 114 f′ in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The female ribs 126 f′ and male ribs 136 m′ of a given section 112′ are axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 114′ are referred to as being axially nested since their radial overlap is substantially reduced or minimal. Multiple slide and lock sections 112′ may be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

FIG. 12 shows a portion of an axially nested expandable stent section, segment or frame 112″ in accordance with another embodiment. This embodiment illustrates the implementation of additional teeth and lockout points, as discussed further below.

In one embodiment, the drawing of FIG. 12 illustrates two side-by-side, axial or longitudinal stent sections 112 a″ and 112 b″ (shown in phantom lead lines). Thus, axially nested stent sections 112 a″, 112 b″ and structural elements 1141″, 114 m″ are axially or longitudinally coupled.

The section 112″ generally comprises a female structural element 114 f″ and a male structural element 114 m″ radially or circumferentially coupled by a slide and lock articulating mechanism 116 mr. During stent expansion, there is circumferential relative motion between the mating male structural element 114 m″ and female structural element 114 f″ as generally shown by arrows 118″. One or both of the mating male-female structural elements 114 m″ and 114 f″ may slidably move apart.

The female structural element 114 f″ generally comprises a pair of spaced ribs or arms 126 f″ (only one shown). At least a portion of the male structural element 114 m″ extends between the female ribs 126 f″. The male structural element 114 m″ generally comprises a pair of spaced ribs or arms 136 m″ (only one shown).

In the embodiment of FIG. 12, each of the female ribs 126 f″ includes a plurality of inwardly extending spaced stops, teeth or tabs 132 f″ that engage the male structural element 114 m″ and each of the male ribs 136 m″ includes a plurality of outwardly extending spaced stops, teeth or tabs 142 m″ that engage the female structural element 114 f″ and its stops 132 f″. The stops 132 f″ and 142 m″ are configured to permit one-way slidable relative motion between the male and female structural elements 114 m″, 114 f″.

During stent expansion, the stops 1321″ and the stops 142 m″ cross one another. This is accomplished by utilizing an axially deflecting mechanism. Thus, during “cross-over” the female ribs 126 f″ and/or the male ribs 136 m″ are respectively deflected outwards and inwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 144″. In one embodiment, spring elements facilitate this rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

As indicated above, either the female ribs 126 f″, the male ribs 136 m″, both or any other suitable combination of ribs may axially deflect to achieve the desired expansion and other deployment characteristics. The axial deflection is caused by the generation of a generally axial or longitudinal force when the female stops 1321″ and respective male stops 142 m″ slide over, engage or abut one another. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 114 m″ and female structural elements 114 f″ in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The female ribs 126 f″ and male ribs 136 m″ of a given section 112″ are axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 114″ are referred to as being axially nested since their radial overlap is substantially reduced or minimal. The slide and lock sections 112″ may be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

FIGS. 13A and 13B show a pair of longitudinally arranged and axially nested expandable stent sections, segments or frames 212 a′, 212 b′ in accordance with one embodiment. Each section 212 a′, 212 b′ comprises at least one structural element 214 a′, 214 b′ respectively. Structural elements 214 a′, 214 b′ of respective adjacent sections 212 a′, 212 b′ are axially or longitudinally coupled to one another by a one-way slide and lock articulating mechanism 216 ab′. As discussed further below, one or more capture wings are provided that keeps the parts 214 a′, 214 b′ coupled and generally side by side.

During stent expansion, there is circumferential relative motion between the mating structural element 214 a′ and structural element 214 b′ as generally shown by arrows 218′. One or both of the mating structural elements 214 a′ and 214 b′ may slidably move apart.

The structural element 214 a′ generally comprises a pair of ribs or arms 226 a′, 236 a′ spaced by end portions 228 a′. The structural element 214 b′ generally comprises a pair of ribs or arms 226 b′, 236 b′ spaced by end portions 228 b′. The ribs 236 a′ and 226 b′ are axially or longitudinally coupled.

The rib 236 a′ includes a slot 260 a′ along substantially its entire length to create a deflectable member 262 a′. The deflectable member 262 a′ has a plurality of spaced stops, teeth or tabs 242 a′ that engage the rib 226 b′ of the structural element 214 b′. The rib 226 b′ has a plurality of spaced stops, teeth or tabs 232 b′ that engage the opposed stops 242 a′ during stent expansion. The stops 242 a′ and 232 b′ are configured to permit one-way slidable relative motion between the structural elements 214 a′, 214 b′.

During stent expansion, the stops 242 a′ and the stops 232 b′ cross one another. This is accomplished by utilizing an axially deflecting mechanism. Thus, during “cross-over” the deflectable member 262 a′ is deflected and then resumes its original undeflected position. This axial motion is generally denoted by arrows 244′. The axial deflection is caused by the generation of a generally axial or longitudinal force when the stops 242 a′ and respective stops 232 b′ slide over, engage or abut one another. In a modified embodiment, spring elements may facilitate rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

The rib 226 b′ further includes a overlapping capture wings or elements 264 b′ and 266 b′ that axially or longitudinally connect the ribs 226 b′ and 236 a′. The capture wing 264 b′ is raised relative to the stops 242 a′, 232 b′ and extends over the deflectable member 262 a′. The capture wing 266 b′ is lowered relative to the stops 242 a′, 232 b′ and extends below the deflectable member 262 a′. Any number of capture wings may be utilized with efficacy, as needed or desired.

The capture wings 264 b′, 266 b′ maintain a coupling between the structural elements 214 a′, 214 b′ and keep them in a generally side by side plane in the collapsed state and as the stent expands. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

The rib 226 a′ is generally similar in structure to the rib 226 b′ and includes stops, teeth or tabs 232 a′, overlapping capture wings or elements 264 a′ and 266 a′. The rib 236 b′ is generally similar in structure to the rib 236 a′ and includes stops, teeth or tabs 242 b′, a slot 260 b′ and a deflectable member 262 b′.

Advantageously, there is substantially no or minimal overlap between axially nesting structural elements 214 a′ and 214 b′ in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The articulating ribs 236 a′, 226 b′ of axially adjacent structural elements 214 a′, 214 b′ are axially displaced from one another. Also, the ribs and elements of a given section 212′ are axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 214′ are referred to as being axially nested since their radial overlap is substantially reduced or minimal. The slide and lock sections 212′ may also be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

FIGS. 14A and 14B show a pair of longitudinally arranged and axially nested expandable stent sections, segments or frames 212 a″, 212 b″ in accordance with another embodiment. Each section 212 a″, 212 b″ comprises at least one structural element 214 a″, 214 b″ respectively. Structural elements 214 a″, 214 b″ of respective adjacent sections 212 a″, 212 b″ are axially or longitudinally coupled to one another by a one-way slide and lock articulating mechanism 216ab″. As discussed further below, one or more capture wings are provided that keeps the parts 214 a″, 214 b″ coupled and generally side by side.

During stent expansion, there is circumferential relative motion between the mating structural element 214 a″ and structural element 214 b″ as generally shown by arrows 218″. One or both of the mating structural elements 214 a″ and 214 b″ may slidably move apart.

The structural element 214 a″ generally comprises a pair of ribs or arms 226 a″, 236 a″ spaced by end portions 228 a″. The structural element 214 b″ generally comprises a pair of ribs or arms 226 b″, 236 b″ spaced by end portions 228 b′. The ribs 236 a″ and 226 b″ are axially or longitudinally coupled.

The rib 236 a″ has a plurality of spaced stops, teeth or tabs 242 a″ that engage the rib 226 b″ of the structural element 214 b″. The rib 226 b″ has a plurality of spaced stops, teeth or tabs 232 b″ that engage the opposed stops 242 a″ during stent expansion. The stops 242 a″ and 232 b″ are configured to permit one-way slidable relative motion between the structural elements 214 a″, 214 b″.

The embodiment of FIGS. 14A and 14B utilizes a substantially axial deflecting mechanism during stent expansion in which the structural elements 214 a″, 214 b″ and/or the sections 212 a″, 212 b″ are deflectable in substantially their entirety. This may be accomplished by utilizing spring linkage elements or the like that facilitate element deflection by providing a resilient biasing mechanism to achieve substantially elastic deflection or deformation.

During stent expansion, the stops 242 a″ and the stops 232 b″ cross one another. This is accomplished by utilizing an axially deflecting mechanism. Thus, during “cross-over” the structural element 236 a″ is deflected and then resumes its original undeflected position. This axial motion is generally denoted by arrows 244″. The axial deflection is caused by the generation of a generally axial or longitudinal force when the generally rigid stops 242 a″ and associated generally rigid stops 232 b″ slide over, engage or abut one another

The rib 226 b″ further includes overlapping capture wings or elements 264 b″ and elements 266 b″ that axially or longitudinally connect the ribs 226 b″ and 236 a″. The capture wings 264 b″ are raised relative to the stops 242 a″, 232 b″ and extend over the rib 236 a″. The capture wing 266 b″ is lowered relative to the stops 242 a″, 232 b″ and extends below the rib 236 a″. Any number of capture wings may be utilized with efficacy, as needed or desired.

The capture wings 264 b″, 266 b″ maintain a coupling between the structural elements 214 a″, 214 b″ and keep them in a generally side by side plane in the collapsed state and as the stent expands. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

The rib 226 a″ is generally similar in structure to the rib 226 b″ and includes stops, teeth or tabs 232 a″, overlapping capture wings or elements 264 a″ and 266 a″. The rib 236 b″ is generally similar in structure to the rib 236 a′ and includes stops, teeth or tabs 242 b″.

Advantageously, there is substantially no or minimal overlap between axially nesting structural elements 214 a″ and 214 b″ in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The articulating ribs 236 a″, 226 b″ of axially adjacent structural elements 214 a″, 214 b″ are axially displaced from one another. Also, the ribs and elements of a given section 212″ are axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 214″ are referred to as being axially nested since their radial overlap is substantially reduced or minimal. The slide and lock sections 212″ may also be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

FIG. 15 shows a portion of an axially nested expandable stent section, segment or frame 312′ in accordance with one embodiment. The section 312′ generally comprises a male structural element 314 m′ and a female structural element 314 f′ radially or circumferentially coupled by a slide and lock articulating mechanism 316 mf′. During stent expansion, there is circumferential relative motion between the mating male structural element 314 m′ and female structural element 314 f′ as generally shown by arrows 318′. One or both of the mating male-female structural elements 314 m′ and 314 f′ may slidably move apart.

The female structural element 314 f′ generally comprises a pair of spaced ribs or arms 326 f′ (only one shown). At least a portion of the male structural element 314 m′ extends between the female ribs 326 f′. The male structural element 314 m′ generally comprises a pair of spaced ribs or arms 336 m′ (only one shown).

In the embodiment of FIG. 15, each of the female ribs 326 f′ includes a plurality of spaced stops, teeth or tabs 332 f′ that engage the male structural element 314 m′ and each of the male ribs 336 m′ includes a plurality of spaced stops, teeth or tabs 342 m′ that engage the female structural element 314 f′ and its stops 332 f′. The stops 332 f′ and 342 m′ are configured to permit one-way slidable relative motion between the male and female structural elements 314 m′, 314 f′.

During stent expansion, the stops 332 f′ and the stops 342 m′ cross or slide over one another. This is accomplished by utilizing a radially deflecting mechanism. Thus, during “cross-over” the female ribs 326 f′ and/or the male ribs 336 m′ are deflected radially and then resume their original undeflected position. This radial motion is generally denoted by arrows 344′. In one embodiment, spring elements facilitate this rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

As indicated above, either the female ribs 326 f′, the male ribs 336 m′, both or any other suitable combination of ribs may radially deflect to achieve the desired expansion and other deployment characteristics. The radial deflection is caused by the generation of a generally radial force when the female stops 332 f′ and respective male stops 342 m′ slide over, engage or abut one another. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

Advantageously, there is substantially minimal overlap between nesting male structural elements 314 m′ and female structural elements 314 f′ in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The radial thickness of overlapping stops or elements 332 f′, 342 m′ is between about the same as the stent material nominal thickness and about two times the stent material nominal thickness. The female ribs 326 f′ and male ribs 336 m′ of a given section 312′ are substantially axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 314′ are referred to as being axially nested since their radial overlap is substantially reduced or minimal. The slide and lock sections 312′ may be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

In one embodiment, the drawing of FIG. 15 illustrates two substantially side-by-side, axial or longitudinal stent sections 312 a′ and 312 b′ (shown in phantom lead lines). Thus, axially nested stent sections 312 a′, 312 b′ and structural elements 314 f′, 314 m′ are axially or longitudinally coupled with minimal radial overlap. The radial thickness of overlapping stops, teeth or elements 332 f′, 342 m′ is between about the same as the stent material nominal thickness and about two times the stent material nominal thickness.

FIG. 16 shows an axially nested expandable stent section, segment or frame 312″ in accordance with another embodiment. FIG. 17 is an enlarged view of the axially, longitudinally or non-radially overlapping design mechanism in a locked position and FIG. 18 is an enlarged view showing radial rib deflection in a sliding position.

The section 312″ includes a pair of male structural elements 314 m 1″, 314 m 2″ and a pair of female structural elements 314 f 1″, 314 f 2″ that respectively slidingly mate via respective interlocking articulating mechanisms 316 mf 1″, 316 mf 2″. In modified embodiments, fewer or more structural elements may be efficaciously utilized, as needed or desired.

During stent expansion, there is circumferential relative motion between the mating male structural elements 314 m 1″, 314 m 2″ and female structural elements 314 f 1″, 314 f 2″ as generally shown by arrows 318″. One or both of the mating male-female structural elements 314 m 1″, 314 f 1″ and 314 m 2″, 314 f 2″ may slidably move apart.

The female structural element 314 f 1″ generally comprises a pair of spaced ribs or arms 326 f 1″ to form a gap 330 f 1″ therebetween. Each of the ribs 326 f 1″ includes a plurality of spaced radially extending stops, teeth or tabs 332 f 1″ that engage the male structural element 314 m 1″.

The female structural element 314 f 2″ generally comprises a pair of spaced ribs or arms 326 f 2″ to form a gap 330 f 2″ therebetween. Each of the ribs 326 f 2″ includes a plurality of spaced radially extending stops, teeth or tabs 332 f 2″ that engage the male structural element 314 m 2″.

The female structural elements 314 f 1″, 314 f 2″ share a common end portion 328″ to which the ribs 326 f 1″ and 326 f 2″ are connected. In one embodiment, the female structural elements 314 f 1″, 314 f 2″ comprise an integral unit. In modified embodiments, the female structural elements 314 f 1″, 314 f 2″ can efficaciously be connected by other techniques, as needed or desired.

The male structural element 314 m 1″ generally comprises a rib or arm 336 m 1″ with a pair of axially extending stops, teeth, tabs or wings 342 m 1″ that engage the female structural element 314 f 1″ and its stops 332 f 1″. In the collapsed and partially expanded states, the rib 336 m 1″ extends into the gap 330 f 1″ between the female ribs 326 f 1″. The stops 332 f 1″, 342 m 1″ are configured to permit one-way slidable relative motion between the male and female structural elements 314 m 1″, 314 f 1″.

The male structural element 314 m 2″ generally comprises a rib or arm 336 m 2″ with a pair of axially extending stops, teeth, tabs or wings 342 m 2″ that engage the female structural element 314 f 2″ and its stops 332 f 2″. In the collapsed and partially expanded states, the rib 336 m 2″ extends into the gap 330 f 2″ between the female ribs 326 f 2″. The stops 332 f 2″, 342 m 2″ are configured to permit one-way slidable relative motion between the male and female structural elements 314 m 2″, 314 f 2″.

The male structural elements 314 m 1″, 314 m 2″ can share a common end portion to which the ribs 336 m 1″ and 336 m 2″ are connected. In one embodiment, the male structural elements 314 m 1″, 314 m 2″ comprise an integral unit. In modified embodiments, the male structural elements 314 m 1″, 314 m 2″ can efficaciously be connected by other techniques, as needed or desired.

During stent expansion, there is circumferential relative motion between the female ribs 326 f 1″ and male rib 336 m 1″ with one or both slidably moving apart. Similarly, there is circumferential relative motion between the female ribs 326 f 2″ and male rib 336 m 2″ with one or both slidably moving apart. The motion is generally denoted by arrows 318″.

The female stops 332 f 1″, 332 f 2″ are configured so that they have generally flat respective end surfaces 346 f 1″, 346 f 2″ to substantially reduce or minimize recoil and generally tapered respective engaging surfaces 348 f 1″, 348 f 2″ to facilitate one-way sliding. The male stops 342 m 1″, 342 m 2″ may also be similarly configured to substantially reduce or minimize recoil and facilitate one-way sliding. Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

During stent expansion, the stops 332 f 1″ and the stops 342 m 1″ cross or slide over one another. This is accomplished by utilizing a radially deflecting mechanism. Thus, and as illustrated by FIGS. 17 and 18, during “cross-over” the female ribs 326 f 1″ and/or the male rib 336 m 1″ are deflected radially and then resume their original undeflected position. This radial motion is generally denoted by arrows 344″.

Similarly, during stent expansion, the stops 332 f 2″ and the stops 342 m 2″ cross or slide over one another. This is accomplished by utilizing a radially deflecting mechanism. Thus, during “cross-over” the female ribs 326 f 2″ and/or the male rib 336 m 2″ are deflected radially and then resume their original undeflected position. This radial motion is generally denoted by arrows 344″. In one embodiment, spring elements facilitate the rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

As indicated above, either the female ribs 326 f 1″, 326 f 2″, the male ribs 336 m 1″, 336 m 2″, both or any other suitable combination of ribs may radially deflect to achieve the desired expansion and other deployment characteristics. The radial deflection is caused by the generation of a generally radial force when the female stops 332 f 1″, 332 f 2″ and respective male stops 342 m 1″, 342 m 2″ slide over, engage or abut one another. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

Advantageously, there is substantially minimal overlap between nesting male structural elements 314 m 1″, 314 m 2″ and respective female structural elements 314 f 1″, 314 f 2″ in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The radial thickness of overlapping elements 314 m 1″, 314 f 1″ and 314 m 2″, 314 f 2″ is between about the same as the stent material nominal thickness and about two times the stent material nominal thickness. The female ribs 3261″ and male rib(s) 336 m″ of a given section 312″ are substantially axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 314″ are referred to as being axially nested since their radial overlap is substantially reduced or minimal. The slide and lock sections 312″ may be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

FIGS. 19 and 20 show a portion of an axially nested expandable stent section, segment or frame 412 in accordance with one embodiment. FIG. 19 illustrates a stent collapsed state and FIG. 20 illustrates a stent expanded state.

The section 412 generally comprises a male structural element 414 m and a female structural element 414 f radially or circumferentially coupled by a slide and lock articulating mechanism 416 mf. During stent expansion, there is circumferential relative motion between the mating male structural element 414 m and female structural element 414 f as generally shown by arrows 418. One or both of the mating male-female structural elements 414 m and 414 f may slidably move apart.

The female structural element 414 f generally comprises a pair of ribs or arms 426 f spaced by an end portion 428 to from a gap 430 f therebetween. In the collapsed state, at least a portion of the male structural element 414 m extends within the gap 430 f.

The male structural element 414 m generally comprises a main rib or arm 436 that bifurcates or divides into two ribs or arms 436 m. The ribs 436 m are spaced by a proximal end portion 438 m 1 and distal end portion 438 m 2 to form a gap 440 m therebetween.

In the embodiment of FIGS. 19 and 20, each of the female ribs 426 f includes a plurality of inwardly extending spaced deflectable fingers or elements 431 f that extend into the gap 430 f. The fingers 431 f terminate in stops, teeth or tabs 432 f that engage the male structural element 414 m.

Each of the male ribs 436 m includes an outwardly extending end stop, tooth or tab 442 m that engage the female structural element 414 f and its stops 432 f. The stops 432 f and 442 m are configured to permit one-way slidable relative motion between the male and female structural elements 414 m, 414 f. The stops 432 f are arranged in an alternating repetitive or staggered pattern for enhanced resolution and greater selection and adaptability in expansion size.

The female stops 432 f are configured so that they have generally flat respective end surfaces 446 f to substantially reduce or minimize recoil and generally tapered respective engaging surfaces 448 f to facilitate one-way sliding. Similarly, the male stops 442 m are configured so that they have generally flat respective end surfaces 450 m to substantially reduce or minimize recoil and generally tapered respective engaging surfaces 452 m to facilitate one-way sliding. Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

During stent expansion, the stops 432 f and the stops 442 m cross one another. This is accomplished by utilizing an axially deflecting mechanism. Thus, during “cross-over” the male stop engaging fingers 431 f deflected generally axially outwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 444. Alternatively, or in addition, deflectable fingers or elements may be provided on the male structural element 414 m.

The axial deflection is caused by the generation of a generally axial or longitudinal force when the female stops 432 f and respective male stops 442 m slide over, engage or abut one another. As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 414 m and female structural elements 414 f in both the stent collapsed state and the stent expanded state, and more particularly in the expanded state. The female ribs 426 f and male ribs 436, 436 m of a given section 412 are axially and/or radially displaced from one another and from the ribs or elements of adjacent sections. Thus, the structural elements 414 are referred to as being axially nested since their radial overlap is substantially reduced or minimal. Multiple slide and lock sections 412 may be connected axially by suitable linkage sections that may include spring elements, as described above and herein.

Some Stent Embodiments

FIGS. 21-27 show conceptual views of embodiments of expandable axially nested slide and lock vascular devices, prostheses or stents 510 in deployed and undeployed states. The stent 510 has a tubular form with a wall comprising a plurality of generally longitudinally arranged linked circumferential sections, segments or frames 512 a, 512 s. The stent 510 has a through lumen 520 which is expandable from a first diameter to a second diameter. The stent 510 and/or the lumen 520 have a generally longitudinal axis 524.

Advantageously, the axially nested embodiments of the stent 510 allow suitable crossing profiles (e.g. luminal size) while maintaining desirable radial strength and luminal patency. In the non-expanded state, there is also minimal or reduced overlap between structural elements, so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device.

The stent 510 comprises alternatingly arranged slide and lock sections 512 a and linkage sections 512 s. Each section 512 a includes a pair of male structural elements 514 m 1, 514 m 2 and a pair of female structural elements 514 f 1, 514 f 2 that each slidingly mate with the male structural elements 514 m 1, 514 m 2 via respective interlocking articulating mechanisms 516 mf 1, 516 mf 2. (Each of the structural elements 514 may also be described as comprising two structural elements since each mates at two circumferential locations.)

As conceptually illustrated in FIG. 21, the articulating mechanisms may comprises radially deflecting locking mechanisms 516r (arrows 544r) or axially (laterally) deflecting locking mechanisms 516 a (arrows 544 a). The number of structural elements in a section and/or the number of sections in a stent may be efficaciously varied and selected, as needed or desired.

The axial or longitudinal coupling between the structural elements 514 of adjacent sections 512 a, the radial coupling between structural elements 514 of the same section 512 a, and the design and configuration of the sections 512 and structural elements 514 are such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 514 in both the non-expanded and expanded states. Thus, the structural elements 514, sections 512 and/or stent 510 are referred to as being axially, longitudinally or non-radially nested. (There is also minimal or reduced radial overlap between linkage elements 522 of the same and adjacent sections 512 s in both the undeployed and deployed states.)

One of the stent sections 512 a′ generally comprises male structural elements 514 m 1′, 514 m 2′ and female structural elements 514 f 1′, 514 f 2′. The proximate stent section 512 a″ generally includes male structural elements 514 m 1″, 514 m 2″ and female structural elements 514 f 1″, 514 f 2″. (The sections 512 a′, 512 a″ are generally similar in structure except for being angularly offset and this nomenclature is used in some instances to provide a more clear description—the use of 512 a encompasses one or both of 512 a′ and 512 a″ as does other similar use of ‘prime’ and “double-prime”.)

The female structural element 514 f 1′ generally comprises a pair of ribs or arms 526 f 1′ spaced by end portions 528 f 11′, 528 f 12′. As discussed above and below herein, the end portions 528 f 11′, 528 f 12′ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective male structural elements 514 m 1′, 514 m 2′ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out.

The female structural element 514 f 2′ generally comprises a pair of ribs or arms 526 f 2′ spaced by end portions 528 f 21′, 528 f 22′. As discussed above and below herein, the end portions 528 f 21′, 528 f 22′ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective female structural elements 514 m 2′, 514 m 1′ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out.

The male structural element 514 m 1′ generally comprises a rib or arm 536 m 11′ and a pair of spaced ribs or arms 536 m 12′ extending in a direction opposite to the rib 536 m 11′. The ribs 536 m 11′, 536 m 12′ share a common end portion 538 m 1′. In the stent collapsed state, the male rib 536 m 11′ extends in the gap between the female ribs 526 f 1′ and the male ribs 536 m 12′ extend in the gap between the female ribs 526 f 2′.

As discussed above and below herein, the ribs 536 m 11′, 536 m 12′ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective female structural elements 514 f 1′, 514 f 2′ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out. More specifically, the ribs 536 m 11′, 536 m 12′ engage respective female end portions 528 f 11′, 528 f 22′.

The male structural element 514 m 2′ generally comprises a rib or arm 536 m 21′ and a pair of spaced ribs or arms 536 m 22′ extending in a direction opposite to the rib 536 m 21′. The ribs 536 m 21′, 536 m 22′ share a common end portion 538 m 2′. In the stent collapsed state, the male rib 536 m 21′ extends in the gap between the female ribs 526 f 2′ and the male ribs 536 m 22′ extend in the gap between the female ribs 526 f 1′.

As discussed above and below herein, the ribs 536 m 21′, 536 m 22′ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective female structural elements 514 f 2′, 514 f 1′ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out. More specifically, the ribs 536 m 21′, 536 m 22′ engage respective female end portions 528 f 21′, 528 f 12′.

The female structural element 514 f 1″ generally comprises a pair of ribs or arms 526 f 1″ spaced by end portions 528 f 11″, 528 f 12″. As discussed above and below herein, the end portions 528 f 11″, 528 f 12″ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective male structural elements 514 m 2″, 514 m 1″ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out.

The female structural element 514 f 2″ generally comprises a pair of ribs or arms 526 f 2″ spaced by end portions 528 f 21″, 528 f 22″. As discussed above and below herein, the end portions 528 f 21″, 528 f 22″ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective male structural elements 514 m 1″, 514 m 2″ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out.

The male structural element 514 m 1″ generally comprises a rib or arm 536 m 11″ and a pair of spaced ribs or arms 536 m 12″ extending in a direction opposite to the rib 536 m 11″. The ribs 536 m 11″, 536 m 12″ share a common end portion 538 m 1″. In the stent collapsed state, the male rib 536 m 11″ extends in the gap between the female ribs 526 f 2″ and the male ribs 536 m 12″ extend in the gap between the female ribs 526 f 1″.

As discussed above and below herein, the ribs 536 m 11″, 536 m 12″ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective female structural elements 514 f 2″, 514 f 1″ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out. More specifically, the ribs 536 m 11″, 536 m 12″ engage respective female end portions 528 f 21″, 528 f 12″.

The male structural element 514 m 2″ generally comprises a rib or arm 536 m 21″ and a pair of spaced ribs or arms 536 m 22″ extending in a direction opposite to the rib 536 m 21″. The ribs 536 m 21″, 536 m 22″ share a common end portion 538 m 2″. In the stent collapsed state, the male rib 536 m 21″ extends in the gap between the female ribs 526 f 1″ and the male ribs 536 m 22″ extend in the gap between the female ribs 526 f 2″.

As discussed above and below herein, the ribs 536 m 21″, 536 m 22″ have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective female structural elements 514 f 1″, 514 f 2″ to provide radially and/or axially deflecting mechanisms for stent expansion and lock-out. More specifically, the ribs 536 m 21″, 536 m 22″ engage respective female end portions 528 f 11″, 528 f 22″.

Each linkage section 512 s includes a plurality of elements 522 and connects adjacent stent sections 512 a′ and 512 a″. One or more of the linkage elements 522 may comprise spring elements. The spring elements 522 provide flexibility and allow expansion of the linkage sections 512 s along with stent expansion. The spring elements 522 also allow for radial and/or axial rib deflection during stent expansion to a deployed state. The spring elements 522 facilitate this rib deflection by providing a resilient biasing mechanism to achieve substantially elastic rib deflection or deformation.

In one embodiment, each linkage section 512 s generally comprises four linkage elements 522 m 1, 522 m 2, 522 f 1, 522 f 2. In modified embodiments, fewer or more linkage elements may be efficaciously utilized, as needed or desired.

The linkage elements 522 m 1 axially or longitudinally connect the male structural elements 514 m 1 (514 m 1′, 514 m 1″). In one embodiment, the linkage elements 522 m 1 and the male structural elements 514 m 1 comprise an integral unit. In modified embodiments, the linkage elements 522 m 1 and the male structural elements 514 m 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 522 m 2 axially or longitudinally connect the male structural elements 514 m 2 (514 m 2′, 514 m 2″). In one embodiment, the linkage elements 522 m 2 and the male structural elements 514 m 2 comprise an integral unit. In modified embodiments, the linkage elements 522 m 2 and the male structural elements 514 m 2 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 522 f 1 axially or longitudinally connect the female structural elements 514 f 1 (514 f 1′, 514 f 1″). In one embodiment, the linkage elements 522 f 1 and the female structural elements 514 f 1 comprise an integral unit. In modified embodiments, the linkage elements 522 f 1 and the female structural elements 514 f 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 522 f 2 axially or longitudinally connect the female structural elements 514 f 2 (514 f 2′, 514 f 2″). In one embodiment, the linkage elements 522 f 2 and the female structural elements 514 f 2 comprise an integral unit. In modified embodiments, the linkage elements 522 f 2 and the female structural elements 514 f 2 can efficaciously be connected by other techniques, as needed or desired.

During stent expansion, there is circumferential relative motion between the mating male structural elements 514 m 1, 514 m 2 and female structural elements 514 f 1, 514 f 2 as generally shown by arrows 518. One or both of the male structural elements 514 m 1, 514 m 2, one or both of the female structural elements 514 f 1, 514 f 2, both the male and female structural elements 514 m 1, 514 m 2, 514 f 1, 514 f 2, or any suitable combination thereof may slidably move apart.

More specifically, during expansion, there is circumferential relative motion between: the female ribs 526 f 1′ and the male rib 536 m 11′ with one or both slidably moving apart; the female ribs 526 f 1′ and the male ribs 536 m 22′ with one or both slidably moving apart; the female ribs 526 f 2′ and the male rib 536 m 21′ with one or both slidably moving apart; and the female ribs 526 f 2′ and the male ribs 536 m 12′ with one or both slidably moving apart. The motion is generally denoted by arrows 518.

Similarly, during stent expansion, there is circumferential relative motion between: the female ribs 526 f 1″ and the male rib 536 m 21″ with one or both slidably moving apart; the female ribs 526 f 1″ and the male ribs 536 m 12″ with one or both slidably moving apart; the female ribs 526 f 2″ and the male rib 536 m 11″ with one or both slidably moving apart; and the female ribs 526 f 2″ and the male ribs 536 m 22″ with one or both slidably moving apart. The motion is generally denoted by arrows 518.

As discussed herein, at full expansion, a hard stop or end capture mechanism is provided to limit further stent expansion. Each section 512 a can comprise one or more end capture mechanisms such as hard stops, straps or other suitable devices that prevent further expansion between mating male and female structural elements 514 m and 514 f.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 514 m and associated female structural elements 514 f in both the collapsed state and the expanded state, and more particularly in the expanded state. For example, for a given stent section 512 a′, in the collapsed state the female ribs 526 f 1′ and the male ribs 536 m 11′, 536 m 22′ are substantially axially or longitudinally displaced or offset while in the expanded state the same are substantially radially or circumferentially displaced or offset, thereby minimizing radial overlap in both the collapsed and expanded states.

Also, for axially displaced stent sections 512 a′ and 512 a″, for example, the female ribs 526 f 1′ and the male rib 536 m 1″ are substantially axially or longitudinally displaced or offset from the female ribs 526 f 1″ and male ribs 536 m 12″. Thus, the stent 510, its sections 512 a and/or structural elements 514 are referred to as being axially nested since their radial overlap is substantially reduced or minimal in both the collapsed and expanded sates.

Referring in particular to FIGS. 24 and 27, the stent 510 has a minor inner collapsed diameter D_(i-collapsed), a major outer collapsed diameter D_(o-collapsed), a minor inner expanded diameter D_(i-expanded) and a major outer expanded diameter D_(o-expanded). The stent wall curvature decreases as the stent 510 expands, but its radius of curvature increases.

The stent wall has a minimum thickness T_(min) and a maximum thickness T_(max). The thicknesses T_(min) and thickness T_(max) remain substantially unchanged in the collapsed and expanded states. In one embodiment, the minimum thickness T_(min) is the thickness of the male structural elements 514 m and the maximum T_(max) is the thickness of the female structural elements 514 f. If the thickness T_(min) is considered to be the nominal material thickness then, in one embodiment, the maximum wall thickness is given by, where k is embodiment dependent: T_(min)<T_(max)≦kT_(min)

In one embodiment k is about two (2). In another embodiment, k is in the range from about 1.5 to about 3, including all values and sub-ranges therebetween. In yet another embodiment, k is in the range from about 1.25 to about 5, including all values and sub-ranges therebetween. In modified embodiments, other suitable values and/or ranges of k may be efficaciously utilized, as needed or desired.

Embodiments of the invention provide an axially nested vascular device 510 to achieve both competitive crossing profiles (e.g. luminal size) while maintaining other key features, such as, for example, radial strength and luminal patency. Advantageously, an axially nested device design allows for use of thicker materials to maintain radial strength, as needed or desired.

The maximum thickness T_(max) is substantially the same in both the collapsed and expanded states. Thus, in the collapsed state, there is also minimal or reduced overlap between structural elements (e.g., 514 m, 514 f), so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device.

During manufacture and assembly of the axially nested embodiments, the device structural elements (e.g., 514 m, 514 f) and/or ribs (e.g. the female ribs 526 f 1′ and the male ribs 536 m 11′, 536 m 22′) are positioned side by side (axially) in the predilated or non-expanded state to substantially reduce or minimize the device crossing profile and bulk in both the undeployed (non-expanded, predilated) and deployed (expanded, dilated) states. Advantageously, by substantially reducing or eliminating the excess bulk typically encountered with a radially nesting device design, embodiments of the invention can be used to achieve competitive devices and crossing profiles with a wide variety of materials at a wide variety of thicknesses, thereby desirably allowing for optimum device design and performance.

FIGS. 28-37 show different views of the axially nested slide and lock vascular device, prosthesis or stent 510. These drawings illustrate, among other things, features of the articulating slide and lock mechanisms, deflecting arm mechanisms and capture mechanisms at full expansion in accordance with some embodiments of the stent 510.

The male rib 536 m 11′ includes a plurality of outwardly extending stops, tabs or teeth 542 m 11′ that extend on both sides of the rib 536 m 11′. The stops 542 m 11′ engage the female structural element 514 f 1′ in a one-way slide and lock articulating motion.

The male stops 542 m 11′ are configured so that they have generally flat end surfaces 550 m 11′ to substantially reduce or minimize recoil and generally tapered engaging surfaces 552 m 11′ to facilitate one-way sliding (see, for example, FIGS. 31 and 33). Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

The male rib 536 m 11′ also includes a pair of outwardly extending end stops, tabs, wings or teeth 542 m 11 e′ with one each extending on each sides of the rib 536 m 11′. The end stops 542 m 11 e′ engage a capture mechanism of the female structural element 514 f 1′ to control and limit the maximum stent expansion.

The end stops 542 m 11 e′ have generally flat engaging surfaces 552 m 11 e′ that facilitate lock-out and capture at full expansion (see, for example, FIGS. 31 and 33). Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

Each of the male ribs 536 m 12′ includes a plurality of outwardly extending stops, tabs or teeth 542 m 12′. The stops 542 m 12′ engage the female structural element 514 f 2′ in a one-way slide and lock articulating motion.

The male stops 542 m 12′ are configured so that they have generally flat end surfaces 550 m 21′ to substantially reduce or minimize recoil and generally tapered engaging surfaces 552 m 21′ to facilitate one-way sliding (see, for example, FIG. 34). Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

In one embodiment, one or both of the male ribs 536 m 12′ include one or more inwardly extending stops, tabs or teeth 542 m 12 i′ (see, for example, FIG. 34). These stops 542 m 12 i′ are configured to allow only one-way sliding and provide a mechanism to substantially reduce or minimize recoil.

Each of the male ribs 536 m 12′ also includes an outwardly extending end stop, tab, wing or tooth 542 m 12 e′. The end stops 542 m 12 e′ engage a capture mechanism of the female structural element 514 f 2′ to control and limit the maximum stent expansion.

The end stops 542 m 12 e′ have generally flat engaging surfaces 552 m 12 e′ that facilitate lock-out and capture at full expansion (see, for example, FIG. 34). Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

The male rib 536 m 21′ includes a plurality of outwardly extending stops, tabs or teeth 542 m 21′ that extend on both sides of the rib 536 m 21′. The stops 542 m 21′ engage the female structural element 514 f 2′ in a one-way slide and lock articulating motion.

The male stops 542 m 21′ are configured so that they have generally flat end surfaces 550 m 21′ to substantially reduce or minimize recoil and generally tapered engaging surfaces 552 m 21′ to facilitate one-way sliding (see, for example, FIG. 34). Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

The male rib 536 m 21′ also includes a pair of outwardly extending end stops, tabs, wings or teeth 542 m 21 e′ with one each extending on each sides of the rib 536 m 21′. The end stops 542 m 21 e′ engage a capture mechanism of the female structural element 514 f 2′ to control and limit the maximum stent expansion.

The end stops 542 m 21 e′ have generally flat engaging surfaces 552 m 21 e′ that facilitate lock-out and capture at full expansion (see, for example, FIG. 32). Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

Each of the male ribs 536 m 22′ includes a plurality of outwardly extending stops, tabs or teeth 542 m 22′. The stops 542 m 22′ engage the female structural element 514 f 1′ in a one-way slide and lock articulating motion.

The male stops 542 m 12′ are configured so that they have generally flat end surfaces 550 m 22′ to substantially reduce or minimize recoil and generally tapered engaging surfaces 552 m 22′ to facilitate one-way sliding (see, for example, FIGS. 31 and 33). Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

In one embodiment, one or both of the male ribs 536 m 22′ include one or more inwardly extending stops, tabs or teeth 542 m 22 i′ (see, for example, FIG. 34). These stops 542 m 22 i′ are configured to allow only one-way sliding and provide a mechanism to substantially reduce or minimize recoil.

Each of the male ribs 536 m 22′ also includes an outwardly extending end stop, tab, wing or tooth 542 m 22 e′. The end stops 542 m 22 e′ engage a capture mechanism of the female structural element 514 f 1′ to control and limit the maximum stent expansion.

The end stops 542 m 22 e′ have generally flat engaging surfaces 552 m 22 e′ that facilitate lock-out and capture at full expansion (see, for example, FIGS. 31 and 33). Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

The female structural elements 514 f 1′ and 514 f 2′ are of generally similar construction as are the other female structural elements of the stent 510. Thus, for brevity, the female structural element 514 m 1′ is discussed in greater detail below with respect to articulation, lock-out and capture features. It is to be understood that a generally similar arrangement is encompassed by the other male structural elements 514 m of the stent 510.

The end portion 528 f 11′ of the female structural element 514 f 1′ slidingly articulates with the male rib 536 m 11′ as generally denoted by arrows 518. The end portion 528 f 11′ also advantageously provides an internal protected locking mechanism for rib articulation and capture of the rib 536 m 11′ at full stent expansion.

The end portion 528 f 11′ includes a pair of spaced deflectable elements, fingers, stops or tabs 531 f 11′. During expansion, the deflectable elements 531 f 11′ and the respective stops 542 m 11′ cross one another. This is accomplished by utilizing an axially deflecting mechanism.

Thus, during “cross-over” the deflectable elements 531 f 11′ are deflected outwards and then resume their original undeflected position. This axial, longitudinal or lateral motion is generally denoted by arrows 544. The axial deflection is caused by the generation of a generally axial or longitudinal force when the deflectable elements 531 f 11′ and respective male stops 542 m 11′ slide over, engage or abut one another.

A lock-out and capture mechanism includes one or more spaced end stops, tabs or teeth 532 f 11 e′ that engage respective end hard stops 542 m 11 e′ of the male rib 536 m 11′ at full stent expansion, and prevent further expansion. This provides to control and limit stent expansion to a predetermined deployment diameter.

A raised capture strap or device 554 f 11′ and an associated slot, gap or recess 556 f 11′ can be provided proximate to the hard stops 532 f 11 e′. The capture strap 554 f 11′ can serve to protect and/or align the male rib 536 m 11′ and the articulating and lock-out mechanisms, and also prevent the male rib 536 m 11′ from jumping out of its track. The internal protected articulating and locking mechanisms advantageously allow clearance space at the outer stent periphery which shields and protects the mechanisms from external surface interferences.

The slot 556 f 11′ extends between the end hard stops 532 f 11 e′ and allows passage of the male rib articulating stops 542 m 11′ but prevents the male rib end hard stops 542 m 11 e′ to pass through, thereby desirably providing a lock-out and capture mechanism. The slot 556 f 11′ can also provide protection, clearance space and/or alignment of the male rib 536 m 11′ and its engaging mechanisms, and also prevent the male rib 536 m 11′ from jumping out of its track.

In some embodiments, the end portion 528 f 11′ includes a shielding and alignment strap, device or element 570 f 11′ (see, for example, FIGS. 35 and 36). The raised element 570 f 11′ provides protection, clearance space and/or alignment of the male rib 536 m 11′ and its engaging mechanisms, and also prevents the male rib 536 m 11′ from jumping out of its track.

The end portion 528 f 11′ can also include one or more spaced clearance elements, spaces, gaps or recesses 572 f 11′. Advantageously, the raised portions of the elements 572 f 11′ provide protection, clearance space and/or alignment of the end stops 542 m 22 e′ in particular during the collapsed and initial stages of stent expansion.

The end portion 528 f 12′ of the female structural element 514 f 1′ slidingly articulates with the male ribs 536 m 22′ as generally denoted by arrows 518. The end portion 528 f 12′ also advantageously provides an internal protected locking mechanism for rib articulation and capture of the ribs 536 m 22′ at full stent expansion.

The end portion 528 f 12′ includes a pair of spaced deflectable elements, fingers, stops or tabs 531 f 12′. During expansion, the deflectable elements 531 f 12′ and the respective stops 542 m 22′ cross one another. This is accomplished by utilizing an axially deflecting mechanism.

Thus, during “cross-over” the deflectable elements 531 f 12′ are deflected outwards and then resume their original undeflected position. This axial, longitudinal or lateral motion is generally denoted by arrows 544. The axial deflection is caused by the generation of a generally axial or longitudinal force when the deflectable elements 531 f 12′ and respective male stops 542 m 22′ slide over, engage or abut one another.

A lock-out and capture mechanism includes one or more spaced end stops, tabs or teeth 532 f 12 e′ that engage respective end hard stops 542 m 22 e′ of the male ribs 536 m 22′ at full stent expansion, and prevent further expansion. This provides to control and limit stent expansion to a predetermined deployment diameter.

A pair of raised capture straps or devices 554 f 12′ and associated slots, gaps or recesses 556 f 12′ can be provided proximate to respective hard stops 532 f 12 e′. The capture straps 554 f 12′ can serve to protect and/or align respective male ribs 536 m 22′ and the articulating and lock-out mechanisms, and also prevent the male ribs 536 m 22′ from jumping out of their track. The internal protected articulating and locking mechanisms advantageously allow clearance space at the outer stent periphery which shields and protects the mechanisms from external surface interferences.

The slots 556 f 12′ extend between the end hard stops 532 f 12 e′ and allow passage of respective male rib articulating stops 542 m 22′ but prevent the male rib end hard stops 542 m 22 e′ to pass through, thereby desirably providing a lock-out and capture mechanism. The slots 556 f 12′ can also provide protection, clearance space and/or alignment of respective female ribs 536 f 22′ and their engaging mechanisms, and also prevent the male ribs 536 m 22′ from jumping out of their track.

In some embodiments, the end portion 528 f 12′ includes a shielding and alignment strap, device or element 570 f 12′ (see, for example, FIGS. 35 and 36). The raised element 570 f 12′ is configured to provide protection, clearance space and/or alignment of the female ribs 536 f 22′ and their engaging mechanisms. The raised element 57 f 12′ is also shaped to provide additional stent strength and facilitate a curved structure when the stent 510 is coiled or rolled down. The shape logic of the device 570 f 12′ is to provide a capture element configuration and structural support for the “box” shape and/or to provide stiffness and support to the center section.

The end portion 528 f 12′ can also include a clearance element, space, gap or recess 572 f 12′. Advantageously, the raised portion of the element 572 f 12′ provides protection, clearance space and/or alignment of the male rib 536 m 11′ in particular during the collapsed and initial stages of stent expansion.

Referring in particular to FIG. 30, in one embodiment, the undeployed length L_(underployed) is about 5.1 mm (0.2 inches) and the undeployed stent diameter is about 1.6 mm (0.064 inches). In other embodiments, the undeployed lengths and undeployed diameters may efficaciously be higher or lower, as needed or desired.

Referring in particular to FIG. 32, in one embodiment, the deployed length L_(deployed) is about 10.6 mm (0.419 inches) and the deployed stent diameter is about 3.4 mm (0.133 inches). In other embodiments, the deployed lengths and deployed diameters may efficaciously be higher or lower, as needed or desired.

FIG. 38 shows the expandable stent 510 during a phase of its fabrication and assembly. In some embodiments, the stent 510 is formed using a lamination and laser cutting process to yield the structure as shown in FIG. 38. The stent 510 is then rolled into a tubular shape in the collapsed state.

In some embodiments, axially extending rows 513 f 1, 513 m 1, 513 f 2, 513 m 2 can each be formed as an integral unit and then connected and rolled into a tubular form in the collapsed state. This may be accomplished by using an injection molding technique or the like, among others. The row 513 f 1 comprises female structural elements 514 f 1 connected by linkage elements 522 f 1, the row 513 m 1 comprises male structural elements 514 m 1 connected by linkage elements 522 m 1, the row 513 f 2 comprises female structural elements 514 f 2 connected by linkage elements 522 f 2 and the row 513 m 2 comprises male structural elements 514 m 2 connected by linkage elements 522 m 2.

Some Further Stent Embodiments

FIGS. 39-42 show views of an expandable axially nested slide and lock vascular device, prosthesis or stent 610 including deployed and undeployed states. In a rolled configuration, the stent 610 has a tubular form with a wall comprising a plurality of generally longitudinally arranged linked circumferential sections, segments or frames 612 a, 612 s. The stent 610 is expandable from a first diameter to a second diameter.

Advantageously, the axially nested embodiments of the stent 610 allow suitable crossing profiles (e.g. luminal size) while maintaining desirable radial strength and luminal patency. In the non-expanded state, there is also minimal or reduced overlap between structural elements, so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device.

The stent 610 comprises alternatingly arranged slide and lock sections 612 a and linkage sections 612 s. Each section 612 a includes three structural elements 614 mf 1, 614 mf 2, 614 mf 3 that each slidingly mate with one another via respective interlocking articulating mechanisms 616 mf 1, 616 mf 2, 616 mf 3. (Each of the structural elements 614 may also be described as comprising two structural elements—one male and one female—since each mates at two circumferential locations.)

Each linkage section 612 s includes three elements 622 mf 1, 622 mf 2, 622 mf 3. The linkage elements 622 mf 1 connect structural elements 614 mf 1 to form a stent element row 613 mf 1. The linkage elements 622 mf 2 connect structural elements 614 mf 2 to form a stent element row 613 mf 2. The linkage elements 622 mf 3 connect structural elements 614 mf 3 to form a stent element row 613 mf 3. The number of elements in a section or row and the number of sections and rows in a stent may be efficaciously varied and selected, as needed or desired.

One or more of the linkage elements 622 may comprise spring elements. The spring elements 622 provide flexibility and allow expansion of the linkage sections 612 s along with stent expansion. The spring elements 622 also allow for radial and/or axial element or member deflection during stent expansion to a deployed state. The spring elements 622 facilitate this deflection by providing a resilient biasing mechanism to achieve substantially elastic deflection or deformation.

The linkage elements 622 mf 1 axially or longitudinally connect the structural elements 614 mf 1. In one embodiment, the linkage elements 622 mf 1 and the structural elements 614 mf 1 comprise an integral unit, that is, the stent row 613 mf 1 comprises an integral unit. In modified embodiments, the linkage elements 622 mf 1 and the structural elements 614 mf 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 622 mf 2 axially or longitudinally connect the structural elements 614 mf 2. In one embodiment, the linkage elements 622 mf 2 and the structural elements 614 mf 2 comprise an integral unit, that is, the stent row 613 mf 2 comprises an integral unit. In modified embodiments, the linkage elements 622 mf 2 and the structural elements 614 mf 2 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 622 mf 3 axially or longitudinally connect the structural elements 614 mf 3. In one embodiment, the linkage elements 622 mf 3 and the structural elements 614 mf 3 comprise an integral unit, that is, the stent row 613 mf 3 comprises an integral unit. In modified embodiments, the linkage elements 622 mf 3 and the structural elements 614 mf 3 can efficaciously be connected by other techniques, as needed or desired.

In some embodiments, each of the axially extending rows 613 mf 1, 613 mf 2, 613 mf 3 are first formed as independent units that may be independent integral units. The stent rows 613 mf 1, 613 mf 2, 613 mf 3 are then connected and rolled into a tubular form in the collapsed state.

The axial or longitudinal coupling between the structural elements 614 of adjacent sections 612 a, the radial coupling between structural elements 614 of the same section 612 a, and the design and configuration of the sections 612 and structural elements 614 are such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 614 in both the non-expanded and expanded states. Thus, the structural elements 614, sections 612 and/or stent 610 are referred to as being axially, longitudinally or non-radially nested. (There is also minimal or reduced radial overlap between linkage elements 622 of the same and adjacent sections 612 s in both the undeployed and deployed states.)

During stent expansion, there is circumferential relative motion between the mating structural elements 614 mf 1, 614 mf 2, 614 mf 3 as generally shown by arrows 518. One or more or all of structural elements 614 mf 1, 614 mf 2, 614 mf 3 in any suitable combination may slidably move apart.

The structural element 614 mf 1 generally comprises female portion with a pair spaced of ribs or arms 626 f 1 and a male portion with a pair of spaced ribs or arms 636 m 12 terminating in a single rib or arm 636 m 11. The end structural elements 614 mf 1 may comprises side extensions or supports 622 mf 1 e. As discussed above and below herein, the structural element 614 mf 1 has one or more slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs or teeth that engage respective coupled structural elements 614 mf 2, 614 mf 3 to provide radially deflecting mechanisms for stent expansion and lock-out.

The female ribs 626 f 1 are spaced by an end portion 628 f 1. Each of the ribs 626 f 1 includes a cavity 674 f 1 in which a plurality of radially deflectable elements, stops, tabs or teeth 632 f 1 extend. Each of the ribs 626 f 1 further includes slots 654 f 1 that receive a mating portion from the adjacent structural element 614 mf 2. Each of the slots 654 f 1 terminates at the end portion 628 f 1 at a respective one of end hard stops 632 f 1 e that control and limit the maximum stent expansion to a predetermined diameter.

The deflectable elements 632 f 1 engage the male portion of the radially coupled structural element 614 mf 2 in a one-way slide and lock articulating motion. The deflectable elements 632 f 1 are configured so that they have generally flat end surfaces 646 f 1 to substantially reduce or minimize recoil and generally tapered engaging surfaces 648 f 1 to facilitate one-way sliding (see, for example, FIG. 42). Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

The male portion of the structural element 614 mf 1 has a generally central portion 638 m 1 that connects the ribs 636 m 12 and the rib 636 m 11. As discussed further below, the central portion 638 m 1 serves as a hard stop in the stent collapsed state.

Each of the ribs 636 m 12 includes a slot 654 m 12 that receives a mating portion from the adjacent structural element 614 mf 2. Each of the slots 654 m 12 is connected to or is in communication with at least one of the respective female portion slots 654 f 1. The male rib 636 m 11 may also include a slot 654 m 11 that is connected to or is in communication with the slots 654 m 12.

The male rib 636 m 11 includes a pair of outwardly extending end stops, tabs, wings or teeth 642 m 11 e with one each extending on each sides of the rib 636 m 11. The stops 642 m 11 e engage the female portion of the adjacent structural element 614 mf 3 in a one-way slide and lock articulating motion. The stops 642 m 11 e are configured so that they have generally flat end surfaces 650 m 11 e to substantially reduce or minimize recoil. Other suitable configurations that inhibit undesirable recoil may be efficaciously utilized, as needed or desired.

As discussed further below, the end stops 642 m 11 e engage a capture mechanism of a mating structural element to control and limit the maximum stent expansion. The end stops 642 m 11 e are configured to have generally flat engaging surfaces 652 m 11 e that facilitate lock-out and capture at full expansion while allowing one-way slide and lock motion during expansion. Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

The end wings 642 m 11 e are spaced by a generally central raised portion 642 m 11 c. As discussed further below, the central portion 642 m 11 c serves as a hard stop in the stent collapsed state.

The end stops 642 m 11 e have generally flat engaging surfaces 652 m 11 e that facilitate lock-out and capture at full expansion (see, for example, FIG. 42). Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

The structural elements 614 mf 1, 614 mf 2, 614 mf 3 are of generally similar construction. Thus, for brevity, the features of the structural element 614 mf 1 have been discussed in greater detail with respect to articulation, lock-out and capture features. It is to be understood that a generally similar arrangement is encompassed by the other structural elements 614 mf 2 and 614 mf 3 of the stent 610, and similar reference numerals are used herein.

Thus, for example, if the female ribs of the structural element 614 mf 1 are denoted by 626 f 1, then the female ribs of the structural elements 614 mf 2 and 614 mf 3 are respectively denoted by 626 f 2 and 626 f 3, and so on. Similarly, if the male rib of the structural element 614 mf 1 is denoted by 636 m 11, then the male ribs of the structural elements 614 mf 2 and 614 mf 3 are respectively denoted by 636 m 21 and 636 m 31, and so on.

Advantageously, there is substantially no or minimal overlap between nesting structural elements 614 mf 1, 614 mf 2 and 614 mf 3 in both the collapsed state and the expanded state, and more particularly in the expanded state. Thus, the stent 610, its sections 612 a and/or structural elements 614 are referred to as being axially nested.

Embodiments of the invention provide an axially nested vascular device 610 to achieve both competitive crossing profiles (e.g. luminal size) while maintaining other key features, such as, for example, radial strength and luminal patency. Advantageously, an axially nested device design allows for use of thicker materials to maintain radial strength, as needed or desired.

During manufacture and assembly of the axially nested embodiments, the device structural elements (e.g., 614 mf 1, 614 mf 2) and/or ribs (e.g. the female ribs 626 m 1 and the male ribs 636 m 12) are positioned side by side (axially) in the predilated or non-expanded state to substantially reduce or minimize the device crossing profile and bulk in both the undeployed (non-expanded, predilated) and deployed (expanded, dilated) states. Advantageously, by substantially reducing or eliminating the excess bulk typically encountered with a radially nesting device design, embodiments of the invention can be used to achieve competitive devices and crossing profiles with a wide variety of materials at a wide variety of thicknesses, thereby desirably allowing for optimum device design and performance.

The articulation between the structural elements 614 mf 1 and 614 mf 2 of a given stent section 612 a is discussed below. As the skilled artisan will recognize, a similar articulation is applicable to other mating structural elements of the stent 610. Thus, for brevity it is not repeated herein.

In the collapsed state (FIG. 39), the male portion of the structural element 614 mf 2 mates with the structural element 614 mf 1. More specifically, the male rib 636 m 21 extends into the gap between the ribs 636 m 12, the wings 642 m 21 e extend into respective slots 654 m 12 and the raised hard stop 642 m 21 c abuts against the raised portion 638 m 1. Advantageously, in the collapsed state, there is axial nesting between the mating structural elements 614 mf 1 and 614 mf 2 at least in part because the respective ribs 636 m 12 and 636 m 21 are axially or longitudinally displaced or offset from one another.

In the collapsed state, the male ribs 636 m 22 extend into the gap between the female ribs 626 f 1. Again advantageously, in the collapsed state, there is axial nesting between the mating structural elements 614 mf 1 and 614 mf 2 at least in part because the female ribs 626 f 1 and male ribs 636 m 22 are axially or longitudinally displaced or offset from one another.

During stent expansion, there is circumferential relative motion between male ribs 636 m 21, 636 m 22 of the structural element 614 mf 2 and the ribs 636 m 12, 626 f 1 of the structural element 614 mf 1 as generally indicated by arrows 618. The male ribs 636 m 21 withdraw from the gap between the ribs 636 m 12 and the male ribs 636 m 22 withdraw from the gap between the ribs 626 f 1. The wings 642 m 21 e slide within respective slots 654 m 11 such that their relative motion is towards the female ribs 626 f 1.

As the rib 636 m 21 begins to extend out of the gap between the ribs 636 m 12 and into the gap between the ribs 626 f 1, and the ribs 636 m 22 begin to extend out of the gap between the ribs 626 f 1, the wings 642 m 21 e slide into respective slots 654 f 1 and cavities 674 f 1. The wings 642 m 21 e engage the respective deflectable elements, fingers, stops or tabs 632 f 1. Thus, during expansion, the deflectable elements 632 f 1 and the respective wings 642 m 21 e cross one another. This is accomplished by utilizing a generally radially deflecting mechanism.

Thus, during “cross-over” the deflectable elements 632 f 1 are deflected radially inwards and then resume their original undeflected position. This radial motion is generally denoted by arrows 644. The radial deflection is caused by the generation of a generally radial force when the deflectable elements 632 f 1 and respective wings 642 m 21 e slide over, engage or abut one another.

The tapered surfaces 648 f 1 of the deflectable elements 632 f 1 facilitate sliding in one direction. The generally flat end surfaces 646 f 1 of the deflectable elements 632 f 1 and the generally flat end surfaces of the wings 650 m 21 e desirably substantially reduce or minimize recoil.

At full expansion, the hard stops 652 m 21 e of the wings 642 m 21 e and the respective end hard stops 632 f 1 e of the structural element portion 628 f 1 contact, engage or abut against one other, and prevent further stent expansion. This lock-out and capture mechanism provides to control and limit stent expansion to a predetermined deployment diameter.

The internal protected articulating and locking mechanisms of the stent 610 advantageously allow clearance space at the outer stent periphery which shields and protects the mechanisms from external surface interferences. Raised and recessed portions of the structural elements 614 mf provide this shielding, for example, the top portions of the female ribs 626 f 1. The structural elements 614 mf are also configured to facilitate alignment between the mating elements.

Still Further Stent Embodiments

FIGS. 43 and 44 show views of expandable axially nested slide and lock vascular devices, prostheses or stents 710 (710′ and 710″). FIG. 45 shows an enlarged view of an articulating and lock-out mechanism 716 mf 1 of the stent 710″.

In a rolled configuration, the stent 710 has a tubular form with a wall comprising a plurality of generally longitudinally arranged linked circumferential sections, segments or frames 712 a, 712 s. The stent 710 is expandable from a first diameter to a second diameter. (The axially nested stents 710′ and 710″ are generally similar in overall design but their articulating and lock-out mechanisms have different constructions, as discussed further below, in accordance with embodiments of the invention.)

Advantageously, the axially nested embodiments of the stent 710 allow suitable crossing profiles (e.g. luminal size) while maintaining desirable radial strength and luminal patency. In the non-expanded state, there is also minimal or reduced overlap between structural elements, so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device.

The stent 710 comprises alternatingly arranged slide and lock sections 712 a and linkage sections 712 s. Each section 712 a includes a pair of female structural elements 714 f 1, 714 f 2 and a pair of male structural elements 714 m 1, 714 m 2 that each slidingly mate with the female structural elements 714 f 1, 714 f 2 via respective interlocking articulating mechanisms 716 mf 1, 716 mf 2. (Each of the structural elements 714 may also be described as comprising two structural elements since each mates at two circumferential locations.)

As described further below, the articulating mechanisms 716 comprise substantially axially (laterally) deflecting locking mechanisms. The number of structural elements in a section and/or the number of sections in a stent may be efficaciously varied and selected, as needed or desired.

The axial or longitudinal coupling between the structural elements 714 of adjacent sections 712 a, the radial coupling between structural elements 714 of the same section 712 a, and the design and configuration of the sections 712 and structural elements 714 are such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 714 in both the non-expanded and expanded states. Thus, the structural elements 714, sections 712 and/or stent 710 are referred to as being axially, longitudinally or non-radially nested. (There is also minimal or reduced radial overlap between linkage elements 722 of the same and adjacent sections 712 s in both the undeployed and deployed states.)

Each of the stent linkage sections 712 s generally comprises linkage elements 722 m 1, 722 f 1, 722 m 2, 722 f 2 which are connected to respective structural elements 714 m 1, 714 f 1, 714 m 2, 714 f 2. Stent row 713 m 1 generally comprises the elements 714 m 1 and 722 m 1, row 713 f 1 generally comprises the elements 714 f 1 and 722 f 1, row 713 m 2 generally comprises the elements 714 m 2 and 722 m 2, and row 713 f 2 generally comprises the elements 714 f 2 and 722 f 2.

The female structural element 714 f 1 generally comprises a generally central rib, arm or portion 726 f 1 spaced from a pair of side ribs or arms 726 f 11, 726 f 12. End portions 728 f 11, 728 f 12 connect the ribs 726 f 1, 726 f 11, 726 f 22. As discussed above and below herein, the female structural element 714 f 1 and one or more of its ribs 726 f 1, 726 f 11, 726 f 22 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage male structural elements 714 m 1, 714 m 2 to provide axially deflecting mechanisms for stent expansion and lock-out.

The female structural element 714 f 2 generally comprises a generally central rib, arm or portion 726 f 2 spaced from a pair of side ribs or arms 726 f 21, 726 f 22. End portions 728 f 21, 728 f 22 connect the ribs 726 f 2, 726 f 21, 726 f 22. As discussed above and below herein, the female structural element 714 f 2 and one or more of its ribs 726 f 2, 726 f 21, 726 f 22 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage female structural elements 714 f 1, 714 f 2 to provide axially deflecting mechanisms for stent expansion and lock-out.

The male structural element 714 m 1 generally comprises a first rib or arm 736 m 11 and a second rib or arm 736 m 12 extending in opposite directions. The ribs 736 m 11, 736 m 12 share a share a common end portion 738 m 1. In the stent collapsed state, the male rib 736 m 11 extends in the gap between and/or is engaged with the female ribs 726 f 1, 726 f 11 and the male rib 736 m 12 extends in the gap between and/or is engaged with the female ribs 726 f 2, 726 f 22. As discussed above and below herein, the ribs 736 m 11, 736 m 12 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage respective female structural elements 714 f 1, 714 f 2 to provide axially deflecting mechanisms for stent expansion and lock-out.

The male structural element 714 m 2 generally comprises a first rib or arm 736 m 21 and a second rib or arm 736 m 22 extending in opposite directions. The ribs 736 m 21, 736 m 22 share a share a common end portion 738 m 2. In the stent collapsed state, the male rib 736 m 21 extends in the gap between and/or is engaged with the female ribs 726 f 1, 726 f 12 and the male rib 736 m 22 extends in the gap between and/or is engaged with the female ribs 726 f 2, 726 f 21. As discussed above and below herein, the ribs 736 m 21, 736 m 22 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage respective female structural elements 714 f 1, 714 f 2 to provide axially deflecting mechanisms for stent expansion and lock-out.

Each linkage section 712 s includes a plurality of the elements 722 (722 m 1, 722 f 1, 722 m 2, 722 f 2) and connects adjacent stent sections 712 a. One or more of the linkage elements 722 may comprise spring elements. In the embodiment of FIGS. 43 and 44, the spring elements 722 provide device flexibility and can allow expansion of the linkage sections 712 s along with stent expansion.

The linkage elements 722 m 1 axially or longitudinally connect the male structural elements 714 m 1. In one embodiment, the linkage elements 722 m 1 and the male structural elements 714 m 1 comprise an integral unit, that is, the stent row 713 m 1 comprises an integral unit. In modified embodiments, the linkage elements 722 m 1 and the male structural elements 714 m 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 722 m 2 axially or longitudinally connect the male structural elements 714 m 2. In one embodiment, the linkage elements 722 m 2 and the male structural elements 714 m 2 comprise an integral unit, that is, the stent row 713 m 2 comprises an integral unit. In modified embodiments, the linkage elements 722 m 2 and the male structural elements 714 m 2 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 722 f 1 axially or longitudinally connect the female structural elements 714 f 1. In one embodiment, the linkage elements 722 f 1 and the female structural elements 714 f 1 comprise an integral unit, that is, the stent row 713 f 1 comprises an integral unit. In modified embodiments, the linkage elements 722 f 1 and the female structural elements 714 f 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 722 f 2 axially or longitudinally connect the female structural elements 714 f 2. In one embodiment, the linkage elements 722 f 2 and the female structural elements 714 f 2 comprise an integral unit, that is, the stent row 713 f 2 comprises an integral unit. In modified embodiments, the linkage elements 722 f 2 and the female structural elements 714 f 2 can efficaciously be connected by other techniques, as needed or desired.

During stent expansion, there is circumferential relative motion between the mating male structural elements 714 m 1, 714 m 2 and female structural elements 714 f 1, 714 f 2 as generally shown by arrows 718. One or both of the male structural elements 714 m 1, 714 m 2, one or both of the female structural elements 714 f 1, 714 f 2, both the male and female structural elements 714 m 1, 714 m 2, 714 f 1, 714 f 2, or any suitable combination thereof may slidably move apart to achieve the desired or predetermined expansion.

More specifically, during expansion, there is circumferential relative motion between: the female ribs 726 f 1, 726 f 11 and the male rib 736 m 11 with one or both slidably moving apart; the female ribs 726 f 1, 726 f 12 and the male rib 736 m 21 with one or both slidably moving apart; the female ribs 726 f 2, 726 f 21 and the male rib 736 m 22 with one or both slidably moving apart; and the female ribs 726 f 2, 726 f 22 and the male rib 736 m 12 with one or both slidably moving apart. The motion is generally denoted by arrows 718.

As discussed herein, at full expansion, a capture mechanism is provided to limit further stent expansion to a predetermined deployment diameter. Each section 712 a and/or structural element 714 can comprise one or more capture mechanisms such as straps, hard stops, and the like among other suitable devices that prevent further expansion between mating male and female structural elements 714 m and 714 f and control the maximum expansion. Any of the capture mechanisms as disclosed, taught or suggested herein may efficaciously be used in conjunction with the stent 710 and any of the other stent embodiments, as needed or desired.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 714 m and associated female structural elements 714 f in both the collapsed state and the expanded state, and more particularly in the expanded state. For example, for a given stent section 712 a, in the collapsed state the female ribs 726 f 1, 726 f 11, 726 f 12 and the male ribs 736 m 11, 736 m 21 are substantially axially or longitudinally displaced or offset while in the expanded state the same are substantially radially or circumferentially displaced or offset, thereby minimizing radial overlap in both the collapsed and expanded states. Thus, the stent 710, its sections 712 and/or structural elements 714 are referred to as being axially nested since their radial overlap is substantially reduced or minimal in both the collapsed and expanded states.

Embodiments of the invention provide an axially nested vascular device 710 to achieve both competitive crossing profiles (e.g. luminal size) while maintaining other key features, such as, for example, radial strength and luminal patency. Advantageously, an axially nested device design allows for use of thicker materials to maintain radial strength, as needed or desired.

During manufacture and assembly of the axially nested embodiments, the device structural elements (e.g., 714 m, 714 f) and/or ribs (e.g. the female ribs 726 f 1, 726 f 11, 726 f 12 and the male ribs 736 m 11, 736 m 21) are positioned side by side (axially) in the predilated or non-expanded state to substantially reduce or minimize the device crossing profile and bulk in both the undeployed (non-expanded, predilated) and deployed (expanded, dilated) states. Advantageously, by substantially reducing or eliminating the excess bulk typically encountered with a radially nesting device design, embodiments of the invention can be used to achieve competitive devices and crossing profiles with a wide variety of materials at a wide variety of thicknesses, thereby desirably allowing for optimum device design and performance.

The articulation between the structural elements 714 m 1 and 714 f 1 of a given stent section 712 a is discussed below. As the skilled artisan will recognize, a similar articulation is applicable to other mating structural elements and/or ribs of the stent 710. Thus, for brevity it is not repeated herein.

Referring in particular to FIG. 43, that is the stent 710′, the male rib 736 m 11 includes a pair of outwardly extending deflectable elements, stops, tabs, wings or teeth 742 m′ with one each extending on each side of the rib 736 m 11. The stops 742 m′ engage respective stops, tabs or teeth 732 f′ of the female ribs 726 f 1, 726 f 11 in a one-way slide and lock articulating motion. This is accomplished by utilizing a generally axial deflecting mechanism.

Thus, during “cross-over” the deflectable wings 742 m′ are deflected axially inwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 744. The axial deflection is caused by the generation of a generally axial force when the deflectable wings 742 m′ and respective teeth 732 f′ slide over, engage or abut one another.

The stops 742 m′, 732 f′ are configured to facilitate one-way sliding relative motion as generally shown by arrows 718. The stops 742 m′, 732 f′ are also configured to substantially reduce or minimize recoil. Other suitable configurations that inhibit facilitate one-way motion and undesirable recoil may be efficaciously utilized, as needed or desired.

At full expansion, a hard stop 742 me′ of the male rib 736 m 11 and a safety hard stop 732 fe′ of the structural element portion 728 f 11 contact, engage or abut against one other, and prevent further stent expansion. This lock-out and capture mechanism provides to control and limit stent expansion to a predetermined deployment diameter. The safety stop 742 me′ also prevents the male rib 736 m 11 from jumping off the female ribs 726 f 1, 726 f 11 during deployment and keeps the rib 736 m 11 in its appropriate track.

Referring in particular to FIGS. 44 and 45, that is the stent 710″, the male rib 736 m 11 includes a pair of outwardly extending deflectable elements, stops, tabs, wings or teeth 742 m″ with one each extending on each side of the rib 736 m 11. In the collapsed state, the wings 742 m″ are positioned in a cavity 774 f″ between the female ribs 726 f 1, 726 f 11.

During stent expansion, the wings 742 m″ engage respective internal stops, tabs or teeth 732 f″ of the female ribs 726 f 1, 726 f 11 in a one-way slide and lock articulating motion. This is accomplished by utilizing a generally axial deflecting mechanism.

Thus, during “cross-over” the deflectable wings 742 m″ are deflected axially inwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 744. The axial deflection is caused by the generation of a generally axial force when the deflectable wings 742 m″ and respective teeth 732 f″ slide over, engage or abut one another.

The stops 742 m″, 732 f″ are configured to facilitate one-way sliding relative motion as generally shown by arrows 718. The stops 742 m″, 732 f″ are also configured to substantially reduce or minimize recoil. Other suitable configurations that inhibit facilitate one-way motion and undesirable recoil may be efficaciously utilized, as needed or desired.

The teeth 732 f″ are positioned within respective slots 754 f″ and under respective raised or top portions 756 f″ of respective female ribs 726 f 1, 726 f 11. Thus, the wings 742 m″ also extend into the slots 754 f″. Advantageously, the top portions 756 f″ prevents the male rib 736 m 11 from jumping off the female ribs 726 f 1, 726 f 11 during deployment and keeps the rib 736 m 11 in its appropriate track.

At full expansion, one or more hard stops 732 fe″ of the structural element portion 728 f 11 contact, engage or abut against the wings 742 m″, and prevent further stent expansion. This lock-out and capture mechanism provides to control and limit stent expansion to a predetermined deployment diameter.

FIG. 46 shows a die 776 that is used to fabricate the stent rows 713 f 1, 713 f 2 in accordance with one embodiment. An injection molding process or the like, among others, may be used to form stent rows 713 f 1, 713 f 2 as integral units. The stent rows 713 m 1, 713 m 2 can also be similarly formed as integral units. The axially extending rows 713 f 1, 713 m 1, 713 f 2, 713 m 2 can then be connected and rolled into a tubular form in the collapsed state.

Yet Further Stent Embodiments

FIGS. 47 and 48 show views of expandable axially nested slide and lock vascular devices, prostheses or stents 810 (810′ and 810″). In a rolled configuration, the stent 810 has a tubular form with a wall comprising a plurality of generally longitudinally arranged linked circumferential sections, segments or frames 812 a, 812 s. The stent 810 is expandable from a first diameter to a second diameter. (The axially nested stents 810′ and 810″ are generally similar in overall design but their articulating and lock-out mechanisms may have slightly different constructions, as shown in the drawings, in accordance with embodiments of the invention.)

Advantageously, the axially nested embodiments of the stent 810 allow suitable crossing profiles (e.g. luminal size) while maintaining desirable radial strength and luminal patency. In the non-expanded state, there is also minimal or reduced overlap between structural elements, so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device.

The stent 810 comprises alternatingly arranged slide and lock sections 812 a and linkage sections 812 s. Each section 812 a includes a pair of male structural elements 814 m 1, 814 m 2 and a pair of female structural elements 814 f 1, 814 f 2 that each slidingly mate with the male structural elements 814 m 1, 814 m 2 via respective interlocking articulating mechanisms 816 mf 1, 816 mf 2. (Each of the structural elements 814 may also be described as comprising two structural elements since each mates at two circumferential locations.)

As described further below, the articulating mechanisms 816 comprise substantially radially deflecting locking mechanisms. The number of structural elements in a section and/or the number of sections in a stent may be efficaciously varied and selected, as needed or desired.

The axial or longitudinal coupling between the structural elements 814 of adjacent sections 812 a, the radial coupling between structural elements 814 of the same section 812 a, and the design and configuration of the sections 812 and structural elements 814 are such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 814 in both the non-expanded and expanded states. Thus, the structural elements 814, sections 812 and/or stent 810 are referred to as being axially, longitudinally or non-radially nested. (There is also minimal or reduced radial overlap between linkage elements 822 of the same and adjacent sections 812 s in both the undeployed and deployed states.)

Each of the stent linkage sections 812 s generally comprises linkage elements 822 m 1, 822 f 1, 822 m 2, 822 f 2 which are connected to respective structural elements 814 m 1, 814 f 1, 814 m 2, 814 f 2. Stent row 813 m 1 generally comprises the elements 814 m 1 and 822 m 1, row 813 f 1 generally comprises the elements 814 f 1 and 822 f 1, row 813 m 2 generally comprises the elements 814 m 2 and 822 m 2, and row 813 f 2 generally comprises the elements 814 f 2 and 822 f 2.

The female structural element 814 f 1 generally comprises a generally central rib, arm or portion 826 f 1 spaced from a pair of side ribs or arms 826 f 11, 826 f 12. End portions 828 f 11, 828 f 12 connect the ribs 826 f 1, 826 f 11, 826 f 22. As discussed above and below herein, the female structural element 814 f 1 and one or more of its ribs 826 m 1, 826 m 11, 826 m 22 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage male structural elements 814 m 1, 814 m 2 to provide radially deflecting mechanisms for stent expansion and lock-out.

The female structural element 814 f 2 generally comprises a generally central rib, arm or portion 826 f 2 spaced from a pair of side ribs or arms 826 f 21, 826 f 22. End portions 828 f 21, 828 f 22 connect the ribs 826 f 2, 826 f 21, 826 f 22. As discussed above and below herein, the female structural element 814 f 2 and one or more of its ribs 826 f 2, 826 f 21, 826 f 22 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage male structural elements 814 m 1, 814 m 2 to provide radially deflecting mechanisms for stent expansion and lock-out.

The male structural element 814 m 1 generally comprises a first rib or arm 836 m 11 and a second rib or arm 836 m 12 extending in opposite directions. The ribs 836 m 11, 836 m 12 share a share a common end portion 838 m 1. In the stent collapsed state, the male rib 836 m 11 extends in the gap between and/or is engaged with the female ribs 826 f 1, 826 f 11 and the male rib 836 m 12 extends in the gap between and/or is engaged with the female ribs 826 f 2, 826 f 22. As discussed above and below herein, the ribs 836 f 11, 836 f 12 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage respective female structural elements 814 f 1, 814 f 2 to provide radially deflecting mechanisms for stent expansion and lock-out.

The male structural element 814 m 2 generally comprises a first rib or arm 836 m 21 and a second rib or arm 836 m 22 extending in opposite directions. The ribs 836 m 21, 836 m 22 share a share a common end portion 838 m 2. In the stent collapsed state, the male rib 836 m 21 extends in the gap between and/or is engaged with the female ribs 826 f 1, 826 f 12 and the male rib 836 m 22 extends in the gap between and/or is engaged with the female ribs 826 f 2, 826 f 21. As discussed above and below herein, the ribs 836 m 21, 836 m 22 have slide and lock articulating mechanisms such as tongue-groove configuration stops, tabs, wings or teeth that engage respective female structural elements 814 f 1, 814 f 2 to provide radially deflecting mechanisms for stent expansion and lock-out.

Each linkage section 812 s includes a plurality of the elements 822 (822 m 1, 822 f 1, 822 m 2, 822 f 2) and connects adjacent stent sections 812 a. One or more of the linkage elements 822 may comprise spring elements. In the embodiments of FIGS. 47 and 48, the spring elements 822 provide device flexibility and can allow expansion of the linkage sections 812 s along with stent expansion.

The linkage elements 822 m 1 axially or longitudinally connect the male structural elements 814 m 1. In one embodiment, the linkage elements 822 m 1 and the male structural elements 814 m 1 comprise an integral unit, that is, the stent row 813 m 1 comprises an integral unit. In modified embodiments, the linkage elements 822 m 1 and the male structural elements 814 m 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 822 m 2 axially or longitudinally connect the male structural elements 814 m 2. In one embodiment, the linkage elements 822 m 2 and the male structural elements 814 m 2 comprise an integral unit, that is, the stent row 813 m 2 comprises an integral unit. In modified embodiments, the linkage elements 822 m 2 and the male structural elements 814 m 2 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 822 f 1 axially or longitudinally connect the female structural elements 814 f 1. In one embodiment, the linkage elements 822 f 1 and the female structural elements 814 f 1 comprise an integral unit, that is, the stent row 813 f 1 comprises an integral unit. In modified embodiments, the linkage elements 822 f 1 and the female structural elements 814 f 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 822 f 2 axially or longitudinally connect the female structural elements 814 f 2. In one embodiment, the linkage elements 822 f 2 and the female structural elements 814 f 2 comprise an integral unit, that is, the stent row 813 f 2 comprises an integral unit. In modified embodiments, the linkage elements 822 f 2 and the female structural elements 814 f 2 can efficaciously be connected by other techniques, as needed or desired.

During stent expansion, there is circumferential relative motion between the mating male structural elements 814 m 1, 814 m 2 and female structural elements 814 f 1, 814 f 2 as generally shown by arrows 818. One or both of the male structural elements 814 m 1, 814 m 2, one or both of the female structural elements 814 f 1, 814 f 2, both the male and female structural elements 714 m 1, 714 m 2, 714 f 1, 714 f 2, or any suitable combination thereof may slidably move apart to achieve the desired or predetermined expansion.

More specifically, during expansion, there is circumferential relative motion between: the female ribs 826 f 1, 826 f 11 and the male rib 836 m 11 with one or both slidably moving apart; the female ribs 826 f 1, 826 f 12 and the male rib 836 m 21 with one or both slidably moving apart; the female ribs 826 f 2, 826 f 21 and the male rib 836 m 22 with one or both slidably moving apart; and the female ribs 826 f 2, 826 f 22 and the male rib 836 m 12 with one or both slidably moving apart. The motion is generally denoted by arrows 818.

As discussed herein, at full expansion, a capture mechanism is provided to limit further stent expansion to a predetermined deployment diameter. Each section 812 a and/or structural element 814 can comprise one or more capture mechanisms such as straps, hard stops, and the like among other suitable devices that prevent further expansion between mating male and female structural elements 814 m and 814 f and control the maximum expansion. Any of the capture mechanisms as disclosed, taught or suggested herein may efficaciously be used in conjunction with the stent 810 and any of the other stent embodiments, as needed or desired.

Advantageously, there is substantially no or minimal overlap between nesting male structural elements 814 m and associated female structural elements 814 f in both the collapsed state and the expanded state, and more particularly in the expanded state. For example, for a given stent section 812 a, in the collapsed state the female ribs 826 f 1, 826 f 11, 826 f 12 and the male ribs 836 m 11, 836 m 21 are substantially axially or longitudinally displaced or offset while in the expanded state the same are substantially radially or circumferentially displaced or offset, thereby minimizing radial overlap in both the collapsed and expanded states. Thus, the stent 810, its sections 812 and/or structural elements 814 are referred to as being axially nested since their radial overlap is substantially reduced or minimal in both the collapsed and expanded states.

Embodiments of the invention provide an axially nested vascular device 810 to achieve both competitive crossing profiles (e.g. luminal size) while maintaining other key features, such as, for example, radial strength and luminal patency. Advantageously, an axially nested device design allows for use of thicker materials to maintain radial strength, as needed or desired.

During manufacture and assembly of the axially nested embodiments, the device structural elements (e.g., 814 m, 814 f) and/or ribs (e.g. the female ribs 826 f 1, 826 f 11, 826 f 12 and the male ribs 836 m 11, 836 m 21) are positioned side by side (axially) in the predilated or non-expanded state to substantially reduce or minimize the device crossing profile and bulk in both the undeployed (non-expanded, predilated) and deployed (expanded, dilated) states. Advantageously, by substantially reducing or eliminating the excess bulk typically encountered with a radially nesting device design, embodiments of the invention can be used to achieve competitive devices and crossing profiles with a wide variety of materials at a wide variety of thicknesses, thereby desirably allowing for optimum device design and performance.

The articulation between the structural elements 814 m 1 and 814 f 1 of a given stent section 812 a is discussed below. As the skilled artisan will recognize, a similar articulation is applicable to other mating structural elements and/or ribs of the stent 810. Thus, for brevity it is not repeated herein.

Referring in particular to FIG. 47, that is the stent 810′, the male rib 836 m 11 includes a pair of outwardly extending stops, tabs, wings or teeth 842 m′ with one each extending on each side of the rib 836 m 11. The male rib 836 m 11 also has a radially inwardly pointing bump, stop, tab or tooth 842 mb′.

During stent expansion, the bump 842 mb′ engages respective stops, tabs or teeth 832 f′ of the female ribs 826 f 1, 826 f 11 in a one-way slide and lock articulating motion. This is accomplished by utilizing a generally radial deflecting mechanism.

Thus, during “cross-over” the male rib 836 m 11 is radially outwardly deflected and then resumes its original undeflected position. This radial motion is generally denoted by arrows 844. The radial deflection is caused by the generation of a generally radial force when the bump 842 m′ and respective teeth 832 f′ slide over, engage or abut one another.

The stops 842 m′, 832 f′ are configured to facilitate one-way sliding relative motion as generally shown by arrows 818. The stops 842 m′, 732 f′ are also configured to substantially reduce or minimize recoil. Other suitable configurations that inhibit facilitate one-way motion and undesirable recoil may be efficaciously utilized, as needed or desired.

The wings 842 m″ extend into side slots of one or both of the female ribs 826 f 1, 826 f 11. Advantageously, this prevents the male rib 836 m 11 from jumping off the female ribs 826 f 1, 826 f 11 during deployment and keeps the rib 836 m 11 in its appropriate track.

At full expansion, one or more hard stops 832 fe′ of the structural element portion 828 f 11 contact, engage or abut against the wings 842 m′, and prevent further stent expansion. This lock-out and capture mechanism provides to control and limit stent expansion to a predetermined deployment diameter.

Referring in particular to FIG. 48, that is the stent 810″, the articulating between male and female structural elements 814 m, 814 f is generally similar to that described herein with respect to the stent 810′. Thus, as the skilled artisan will appreciate, it is not repeated herein.

FIG. 49 shows two of the stent rows 813 f 1, 813 f 2 in accordance with one embodiment. An injection molding process or the like, among others, may be used to form stent rows 813 f 1, 813 f 2 as integral units. The stent rows 813 m 1, 813 m 2 can also be similarly formed as integral units. The axially extending rows 813 f 1, 813 m 1, 813 f 2, 813 m 2 can then be connected and rolled into a tubular form in the collapsed state.

FIG. 50 shows an exploded view of a lamination stack 878 used to fabricate the stent rows 813 (813 f 1, 813 f 2) by a lamination process in accordance with one embodiment. The stent rows 813 m 1, 81 mf 2 can also be similarly formed. The axially extending rows 813 f 1, 813 m 1, 813 f 2, 813 m 2 can then be connected and rolled into a tubular form in the collapsed state.

The lamination stack 878 generally comprises three sheets or pallets 878 f 1, 878 f 2, 878 f 3 which have the desired features formed thereon, for example, by laser cutting, etching and the like. The pallets 878 f 1, 878 f 2, 878 f 3 are aligned and joined, for example, by bonding, welding and the like to form a unit. The excess material (e.g., side and end rails) is removed to form the rows 813 (813 f 1, 813 f 2).

The pallet 878 f 1 includes features that correspond to stops engaged by an articulating female rib. The pallet 878 f 2 includes features that correspond to hard stops that control and limit the diameter in collapsed and fully deployed states. The pallet 878 f 3 includes features that correspond to teeth that align and hold the articulating rib in place.

FIGS. 51-56 show various conceptual views of axially nested one-way slide and lock stent geometries and configurations in accordance with embodiments of the invention. The nesting utilizes a “telescope” concept. The drawings show embodiments of stent sections, segments or frames 912 a with structural elements 914 mf. The stent sections include articulating mechanisms that may comprises radially deflecting locking mechanisms or axially (laterally) deflecting locking mechanisms. These slide and lock articulating mechanisms may include tongue-groove configurations stops, tabs, wings or teeth that provide radially and/or axially deflecting mechanisms for stent expansion and lock-out. Any of the articulating mechanism as disclosed, taught or suggested herein including any disclosed, taught or suggested by the embodiments of FIGS. 51-56 may efficaciously be used, as needed or desired.

The embodiments of FIGS. 51-56 can include capture mechanisms that serve to control and limit stent expansion to a predetermined deployment diameter. Each section 912 and/or structural element 914 can comprise one or more capture mechanisms such as straps, hard stops, and the like among other suitable devices that prevent further expansion between mating structural elements 914 and control the maximum expansion. Any of the capture mechanisms as disclosed, taught or suggested herein may efficaciously be used in conjunction with the embodiments of FIGS. 51-56, as needed or desired.

Some Additional Stent Embodiments

FIGS. 57-62 show views of an expandable axially nested slide and lock vascular device, prosthesis or stent 1010 including deployed and undeployed states. In a rolled configuration, the stent 1010 has a tubular form with a wall comprising a plurality of generally longitudinally arranged linked circumferential sections, segments or frames 1012 a, 1012 s. The stent 1010 is expandable from a first diameter to a second diameter. The general design of the stent 1010 may be conceptually characterized as a one-way sliding “telescope-like” configuration.

Advantageously, the axially nested embodiments of the stent 1010 allow suitable crossing profiles (e.g. luminal size) while maintaining desirable radial strength and luminal patency. In the non-expanded state, there is also minimal or reduced overlap between structural elements, so that the luminal size facilitates insertion of a guiding catheter balloon or the like to expand the vascular device.

The stent 1010 comprises alternatingly arranged slide and lock sections 1012 a and linkage sections 1012 s. Each section 1012 a includes three structural elements 1014 mf 1, 1014 mf 2, 1014 mf 3 that each slidingly mate with one another via respective interlocking articulating mechanisms 1016 mf 1, 1016 mf 2, 1016 mf 3. (Each of the structural elements 1014 may also be described as comprising two structural elements—one male and one female—since each mates at two circumferential locations.)

Each linkage section 1012 s includes three elements 1022 mf 1, 1022 mf 2, 1022 mf 3. The linkage elements 1022 mf 1 connect structural elements 1014 mf 1 to form a stent element row 1013 mf 1. The linkage elements 1022 mf 2 connect structural elements 1014 mf 2 to form a stent element row 1013 mf 2. The linkage elements 1022 mf 3 connect structural elements 1014 mf 3 to form a stent element row 1013 mf 3. The number of elements in a section or row and the number of sections and rows in a stent may be efficaciously varied and selected, as needed or desired.

One or more of the linkage elements 1022 may comprise spring elements. The spring elements 1022 provide device flexibility and allow expansion of the linkage sections 1012 s along with stent expansion. The spring elements 1022 can also allow for radial and/or axial element or member deflection during stent expansion to a deployed state. The spring elements 1022 facilitate this deflection by providing a resilient biasing mechanism to achieve substantially elastic deflection or deformation.

The linkage elements 1022 mf 1 axially or longitudinally connect the structural elements 1014 mf 1. In one embodiment, the linkage elements 1022 mf 1 and the structural elements 1014 mf 1 comprise an integral unit, that is, the stent row 1013 mf 1 comprises an integral unit. In modified embodiments, the linkage elements 1022 mf 1 and the structural elements 1014 mf 1 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 1022 mf 2 axially or longitudinally connect the structural elements 1014 mf 2. In one embodiment, the linkage elements 1022 mf 2 and the structural elements 1014 mf 2 comprise an integral unit, that is, the stent row 1013 mf 2 comprises an integral unit. In modified embodiments, the linkage elements 1022 mf 2 and the structural elements 1014 mf 2 can efficaciously be connected by other techniques, as needed or desired.

The linkage elements 1022 mf 3 axially or longitudinally connect the structural elements 1014 mf 3. In one embodiment, the linkage elements 1022 mf 3 and the structural elements 1014 mf 3 comprise an integral unit, that is, the stent row 1013 mf 3 comprises an integral unit. In modified embodiments, the linkage elements 1022 mf 3 and the structural elements 1014 mf 3 can efficaciously be connected by other techniques, as needed or desired.

In some embodiments, each of the axially extending rows 1013 mf 1, 1013 mf 2, 1013 mf 3 are first formed as independent units that may be independent integral units. The stent rows 1013 mf 1, 1013 mf 2, 1013 mf 3 are then connected and rolled into a tubular form in the collapsed state.

The axial or longitudinal coupling between the structural elements 1014 of adjacent sections 1012 a, the radial coupling between structural elements 1014 of the same section 1012 a, and the design and configuration of the sections 1012 and structural elements 1014 are such that there is minimal or reduced overlapping in the radial or circumferential direction between the structural elements 1014, in particular in the expanded or deployed state. Thus, the structural elements 1014, sections 1012 and/or stent 1010 are referred to as being axially, longitudinally or non-radially nested. (There is also minimal or reduced radial overlap between linkage elements 1022 of the same and adjacent sections 1012 s in both the undeployed and deployed states, and more particularly in the deployed state.)

During stent expansion, there is circumferential relative motion between the mating structural elements 1014 mf 1, 1014 mf 2, 1014 mf 3 as generally shown by arrows 1018. One or more or all of structural elements 1014 mf 1, 1014 mf 2, 1014 mf 3 in any suitable combination may slidably move apart.

Each of the structural elements 1014 mf 1, 1014 mf 2, 1014 mf 3 has a generally similar structure and each comprises a male portion and a female portion. Thus, for brevity, only the male portion of the structural element 1014 mf 1 and the female portion of the structural element 1014 mf 2 and their articulation, lock-out and capture features are described in detail below.

It is to be understood that a generally similar arrangement is encompassed by the other structural elements 1014 of the stent 1010, and similar reference numerals are used herein. Thus, for example, if the male ribs of the structural element 1014 mf 1 are denoted by 1036 m 1, then the male ribs of the structural elements 1014 mf 2 and 1014 mf 3 are respectively denoted by 1036 m 2 and 1026 m 3, and so on.

The male portion of the structural element 1014 mf 1 mates or articulates with the female portion of the structural element 1014 mf 2 in a one-way sliding manner. Similarly, the male portion of the structural element 1014 mf 2 mates or articulates with the female portion of the structural element 1014 mf 3 in a one-way sliding manner. Also similarly, the male portion of the structural element 1014 mf 3 mates or articulates with the female portion of the structural element 1014 mf 1 in a one-way sliding manner. As discussed above and below herein, the slide and lock articulating mechanisms of the structural elements 1014 include features such as deflectable elements or members, tongue-groove configuration stops, tabs or teeth that provide axially deflecting mechanisms for stent expansion and lock-out.

The male portion of the structural element 1014 mf 1 generally includes a pair of spaced ribs or arms 1036 m 1 with a gap therebetween. The male ribs 1036 m 1 converge towards one another to terminate and join at a common end portion 1038 m 1.

As best seen in FIGS. 61 and 62, the end portion 1038 m 1 includes a radially inwards extending end tab, tooth or stop 1042 me 1 that terminates in a pair of outwardly and axially extending tabs, teeth, stops or wings 1042 m 1. As discussed further below, the end stop 1042 me 1 engages the female portion of the adjacent structural element 614 mf 2 in a one-way slide and lock articulating motion. The end stop 1014 me 1 is configured to substantially reduce or minimize recoil.

As discussed further below, the end stop 1042 me 1 also serves as a safety hard stop in the collapsed state and at full stent expansion. At full expansion, the end stop 1042 me 1 engages a capture mechanism of the mating structural element 1014 mf 2 to control and limit the maximum stent expansion to a predetermined deployment diameter. Other suitable lock-out and capture configurations may be efficaciously utilized, as needed or desired.

Referring in particular to FIGS. 61 and 62, the female portion of the structural element 1014 mf 2 generally comprises a pair of spaced ribs or arms 1026 f 2 within the gap between the male ribs 1036 m 2. The female ribs 1026 f 2 are radially inwardly recessed relative to the male ribs 1036 m 2 to provide clearance space for the mating male ribs 1036 m 1 in the collapsed state and during stent expansion. The female ribs 1026 f 1 are connected by an end portion 1028 f 1 that has one or more hard stops 1032 fe 2 that control and limit the maximum stent expansion to a predetermined diameter.

Each of the ribs 1026 f 2 includes a pair of spaced sub-ribs, -arms or rails 1026 f 21, 1026 f 22. The rails 1026 f 21 are axially deflectable and have a plurality of inwardly axially extending stops, tabs or teeth 1032 f 2. As discussed further below, the teeth 1032 f 2 engage the male portion of the radially coupled structural element 1014 mf 1 in a one-way slide and lock articulating motion, and in one embodiment, are not deflectable.

The teeth 1032 f 2 are configured so that they have generally flat end surfaces to substantially reduce or minimize recoil and generally tapered engaging surfaces to facilitate one-way sliding. Other suitable configurations that inhibit undesirable recoil and facilitate one-way expansion may be efficaciously utilized, as needed or desired.

Each of the ribs 1026 f 22 includes an axial deflection control device, bump or protrusion 1032 f 22 b that is spaced by a predetermined amount from a respective one of the deflectable rails or ribs 1026 f 21. Advantageously, the bumps 1032 f 22 b serve to control the maximum deflection of the rails or ribs 1026 f 21 so that they do not deform or bend beyond a prescribed range. The bumps 1032 f 22 b also desirably act as “speed bumps” to control deployment and maintain uniformity of deployment.

Advantageously, there is substantially no or minimal overlap between nesting structural elements 1014 mf 1, 1014 mf 2 and 1014 mf 3 in both the collapsed state and the expanded state, and more particularly in the expanded state. Thus, the stent 1010, its sections 1012 a and/or structural elements 1014 are referred to as being axially nested. Any overlap in the collapsed state is such that a suitable crossing profile is still achieved.

Embodiments of the invention provide an axially nested vascular device 1010 to achieve both competitive crossing profiles (e.g. luminal size) while maintaining other key features, such as, for example, radial strength and luminal patency. Advantageously, an axially nested device design allows for use of thicker materials to maintain radial strength, as needed or desired.

During manufacture and assembly of the axially nested embodiments, at least some of the device ribs (e.g. the male ribs 1036 m 1 and the male ribs 1036 m 1) are positioned side by side (axially) in the predilated or non-expanded state to substantially reduce or minimize the device crossing profile and bulk in both the undeployed (non-expanded, predilated) and deployed (expanded, dilated) states. Advantageously, by substantially reducing or eliminating the excess bulk typically encountered with a radially nesting device design, embodiments of the invention can be used to achieve competitive devices and crossing profiles with a wide variety of materials at a wide variety of thicknesses, thereby desirably allowing for optimum device design and performance.

The articulation between the structural elements 1014 mf 1 and 1014 mf 2 of a given stent section 1012 a is discussed below. As the skilled artisan will recognize, a similar articulation is applicable to other mating structural elements of the stent 1010. Thus, for brevity it is not repeated herein.

During stent expansion, there is circumferential relative motion between the ribs of the structural element 1014 mf 1 and the ribs of the structural element 1014 mf 1 as generally indicated by arrows 1018. The male ribs 1036 m 1 withdraw from the gap between the ribs 1036 m 2.

The end stop 1042 me 1 slides within the gap between the female ribs 1026 f 21 and the wings 1042 m 1 slide along the lower or radially inwards surface of the female toothed ribs 1026 f 21. Advantageously, the ribs 1026 f 21 and/or wings 1042 m 1 prevent the male ribs 1036 m 1 from jumping out of their track and keep them in position.

The stop 1042 me 1 engages the teeth 1032 f 2 of the female ribs 1026 f 21. Thus, during expansion, the teeth 1032 f 2 of the deflectable female ribs 1026 f 21 and the stop 1042 me 1 cross one another. This is accomplished by utilizing a generally axially deflecting mechanism.

Thus, during “cross-over” the deflectable female ribs 1026 f 21 are deflected axially outwards and then resume their original undeflected position. This axial motion is generally denoted by arrows 1044. The axial deflection is caused by the generation of a generally axial force when the teeth 1032 f 2 and the stop 1042 me 1 slide over, engage or abut one another. Advantageously, the axial deflection control bumps 1032 f 22 b substantially prevent undesirable or excessive deflection and control deployment to maintain uniformity of deployed stent.

At full expansion, the safety hard stop 1042 me 1 and the respective end hard stops 1032 fe 2 of the structural element portion 1028 f 2 contact, engage or abut against one other, and prevent further stent expansion. This lock-out and capture mechanism provides to control and limit stent expansion to a predetermined deployment diameter.

The internal protected articulating and locking mechanisms of the stent 1010 advantageously allow clearance space at the outer stent periphery which shields and protects the mechanisms from external surface interferences. Raised and recessed portions of the structural elements 1014 mf can provide this shielding and the structural elements 1014 mf are also configured to facilitate alignment between the mating elements.

FIG. 63 shows an expandable axially nested slide and lock vascular device, prosthesis or stent 1010′ in accordance with another embodiment. The stent 1010′ is generally similar to the stent 1010 except that it has linkage sections 1012 s′ that have a modified construction.

Each linkage section 1012 s′ includes three elements 1022 mf′ that are generally similar to one another. Each linkage element 1022 mf′ generally comprises a plurality of interconnected sub-elements 1022 mfs′. One or more of the linkage elements 1022 mf′ and/or the sub-elements 1022 mfs′ may comprise spring elements, as needed or desired.

Metal Stents and Methods of Manufacturing

Preferred materials for making the stents in accordance with some embodiments of the invention include cobalt chrome, 316 stainless steel, tantalum, titanium, tungsten, gold, platinum, iridium, rhodium and alloys thereof or pyrolytic carbon. In still other alternative embodiments, the stents may be formed of a corrodible material, for instance, a magnesium alloy. Although preferred stent embodiments have been described as being conventional balloon expandable stents, those skilled in the art will appreciate that stent constructions according to the present invention may also be formed from a variety of other materials to make a stent crush-recoverable. For example, in alternative embodiments, such as self expandable stents, shape memory alloys that allow for such as Nitinol and Elastinite® may be used in accordance with embodiments of the invention.

Preferably, sheets are work-hardened prior to forming of the individual stent elements to increase strength. Methods of work hardening are well known in the art. Sheets are rolled under tension, annealed under heat and then re-worked. This may be continued until the desired modulus of hardness is obtained. Most stents in commercial use today employ 0% to 10% work hardened material in order to allow for “softer” material to deform to a larger diameter. In contrast, because expansion of the sliding and locking radial elements in accordance with embodiments of the invention depends on sliding rather than material deformation, it is preferred to use harder materials, preferably in the range of about 25-95% work hardened material to allow for thinner stent thickness. More preferably, the stent materials are 50-90% work hardened and most preferably, the materials are 80-85% work hardened.

Preferred methods of forming the individual elements from the metal sheets may be laser cutting, laser ablation, die-cutting, chemical etching, plasma etching and stamping and water jet cutting of either tube or flat sheet material or other methods known in the art which are capable of producing high-resolution components. The method of manufacture, in some embodiments, depends on the material used to form the stent. Chemical etching provides high-resolution components at relatively low price, particularly in comparison to high cost of competitive product laser cutting. Some methods allow for different front and back etch artwork, which could result in chamfered edges, which may be desirable to help improve engagements of lockouts. Further one may use plasma etching or other methods known in the art which are capable of producing high-resolution and polished components. The current invention is not limited to the means by which stent or stent elements can be fabricated.

Once the base geometry is achieved, the elements can be assembled numerous ways. Tack-welding, adhesives, mechanical attachment (snap-together and/or weave together), and other art-recognized methods of attachment, may be used to fasten the individual elements. Some methods allow for different front and back etch artwork, which could result in chamfered edges, which may be desirable to help improve engagements of lockouts. In one preferred method of manufacture, the components of the stent may be heat set at various desired curvatures. For example, the stent may be set to have a diameter equal to that of the deflated balloon, as deployed, at a maximum diameter, or greater than the maximum diameter. In yet another example, elements can be electropolished and then assembled, or electropolished, coated, and then assembled, or assembled and then electropolished.

In another embodiment, in particular with shape memory alloys, the stent is heat set at beyond the maximum diameter then built mid diameter than placed over catheter and reverse ratcheted and locked into smaller diameter and onto catheter with positive catch hold down mechanism to achieve a small profile and excellent retention.

Polymeric Stents

While metal stents possess certain desirable characteristics, the useful lifespan of a stent is estimated to be in the range of about 6 to 9 months, the time at which in-stent restenosis stabilizes and healing plateaus. In contrast to a metal stent, a bioresorbable stent may not outlive its usefulness within the vessel. Moreover, a bioresorbable stent may be used to deliver a greater dose of a therapeutic agent, deliver multiple therapeutic agents at the same time or at various times of its life cycle, to treat specific aspects or events of vascular disease. Additionally, a bioresorbable stent may also allow for repeat treatment of the same approximate region of the blood vessel. Accordingly, there remains an important unmet need to develop temporary (i.e., bioresorbable and/or radiopaque) stents, wherein the polymeric materials used to fabricate these stents have the desirable qualities of metal (e.g., sufficient radial strength and radiopacity, etc.), while circumventing or alleviating the many disadvantages or limitations associated with the use of permanent metal stents.

In one preferred embodiment, the stent may be formed from biocompatible polymers that are bio-resorbable (e.g., bio-erodible or bio-degradable). Bio-resorbable materials are preferably selected from the group consisting of any hydrolytically degradable and/or enzymatically degradable biomaterial. Examples of suitable degradable polymers include, but are not limited to, polyhydroxybutyrate/polyhydroxyvalerate copolymers (PHV/PHB), polyesteramides, polylactic acid, hydroxy acids (i.e. lactide, glycolide, hydroxybutyrate), polyglycolic acid, lactone based polymers, polycaprolactone, poly(propylene fumarate-co-ethylene glycol) copolymer (aka fumarate anhydrides), polyamides, polyanhydride esters, polyanhydrides, polylactic acid/polyglycolic acid with a calcium phosphate glass, polyorthesters, silk-elastin polymers, polyphosphazenes, copolymers of polylactic acid and polyglycolic acid and polycaprolactone, aliphatic polyurethanes, polyhydroxy acids, polyether esters, polyesters, polydepsidpetides, polysaccharides, polyhydroxyalkanoates, and copolymers thereof.

In one mode, the degradable materials are selected from the group consisting of poly(glycolide-trimethylene carbonate), poly(alkylene oxalates), polyaspartimic acid, polyglutarunic acid polymer, poly-p-dioxanone, poly-.beta.-dioxanone, asymmetrically 3,6-substituted poly-1,4-dioxane-2,5-diones, polyalkyl-2-cyanoacrylates, polydepsipeptides (glycine-DL-lactide copolymer), polydihydropyranes, polyalkyl-2-cyanoacrylates, poly-.beta.-maleic acid (PMLA), polyalkanotes and poly-.beta.-alkanoic acids. There are many other degradable materials known in the art. (See e.g., Biomaterials Science: An Introduction to Materials in Medicine (29 Jul. 2004) Ratner, Hoffman, Schoen, and Lemons; and Atala, A., Mooney, D. Synthetic Biodegradable Polymer Scaffolds. 1997 Birkhauser, Boston; incorporated herein by reference).

Further still, in a more preferred embodiment, the stents may be formed of a polycarbonate material, such as, for example, tyrosine-derived polycarbonates, tyrosine-derived polyarylates, iodinated and/or brominated tyrosine-derived polycarbonates, iodinated and/or brominated tyrosine-derived polyarylates. For additional information, see U.S. Pat. Nos. 5,099,060, 5,198,507, 5,587,507, 5,658,995, 6,048,521, 6,120,491, 6,319,492, 6,475,477, 5,317,077, and 5,216,115, each of which is incorporated by reference herein. In another preferred embodiment, the polymer is any of the biocompatible, bioabsorbable, radiopaque polymers disclosed in U.S. Patent Application Nos. 60/601,526; 60/586,796; and 10/952,202 the entire disclosures of which are incorporated herein by reference thereto.

Natural polymers (biopolymers) include any protein or peptide. Preferred biopolymers may be selected from the group consisting of alginate, cellulose and ester, chitosan, collagen, dextran, elastin, fibrin, gelatin, hyaluronic acid, hydroxyapatite, spider silk, cotton, other polypeptides and proteins, and any combinations thereof.

In yet another alternative embodiment, shape-shifting polymers may be used to fabricate stents constructed according to the present invention. Suitable shape-shifting polymers may be selected from the group consisting of polyhydroxy acids, polyorthoesters, polyether esters, polyesters, polyamides, polyesteramides, polydepsidpetides, aliphatic polyurethanes, polysaccharides, polyhydroxyalkanoates, and copolymers thereof. For addition disclosure on bio-degradable shape-shifting polymers, see U.S. Pat. No. 6,160,084, which is incorporated by reference herein. For additional disclosure on shape memory polymers, see U.S. Pat. Nos. 6,388,043 and 6,720,402, each of which are incorporated by reference herein. Further the transition temperature may be set such that the stent is in a collapsed condition at a normal body temperature. However, with the application of heat during stent placement and delivery, such as via a hot balloon catheter or a hot liquid (e.g., saline) perfusion system, the stent expands to assume its final diameter in the body lumen. When a thermal memory material is used, it may provide a crush-recoverable structure.

Further still, stents may be formed from biocompatible polymers that are biostable (e.g., non-degrading and non-erodible). Examples of suitable non-degrading materials include, but are not limited to, polyurethane, Delrin, high density polyethylene, polypropylene, and poly(dimethyl siloxane).

In some embodiments, the layers may comprise or contain any example of thermoplastics, such as the following, among others: fluorinated ethylene-propylene, poly(2-hydroxyethlmethacrylate (aka pHEMA), poly(ethylene terephthalate) fiber (aka Dacron®) or film (Mylar®), poly(methyl methacrylate (aka PMMA), Poly(tetraflouroethylene) (aka PTFE and ePTFE and Gore-Tex®), poly(vinylchloride), polyacrylates and polyacrylonitrile (PAN), polyamides (aka Nylon), polycarbonates and polycarbonate urethanes, polyethylene and poly(ethylene-co-vinyl acetate), polypropylene, polypropylene, polystyrene, polysulphone, polyurethane and polyetherurethane elastomers such as Pellethane® and Estane®, Silicone rubbers, Siloxane, polydimethylsiloxane (aka PDMS), Silastic®, Siliconized Polyurethane.

Methods of Manufacturing and Assembling Polymeric Stents

Where plastic and/or degradable materials are used, the elements may be made using laser ablation with a screen, stencil or mask; solvent casting; forming by stamping, embossing, compression molding, centripetal spin casting and molding; extrusion and cutting, three-dimensional rapid prototyping using solid free-form fabrication technology, stereolithography, selective laser sintering, or the like; etching techniques comprising plasma etching; textile manufacturing methods comprising felting, knitting, or weaving; molding techniques comprising fused deposition modeling, injection molding, room temperature vulcanized molding, or silicone rubber molding; casting techniques comprising casting with solvents, direct shell production casting, investment casting, pressure die casting, resin injection, resin processing electroforming, or injection molding or reaction injection molding. Certain preferred embodiments with the present polymers may be shaped into stents via combinations of two or more thereof, and the like.

Such processes may further include two-dimensional methods of fabrication such as cutting extruded sheets of polymer, via laser cutting, etching, mechanical cutting, or other methods, and assembling the resulting cut portions into stents, or similar methods of three-dimensional fabrication of devices from solid forms. For additional information, see U.S. patent application Ser. No. 10/655,338, which is incorporated by reference herein.

Stents of the preferred embodiment are manufactured with elements prepared in full stent lengths or in partial lengths of which two or more are then connected or attached. If using partial lengths, two or more may be connected or attached to comprise a full length stent. In this arrangement the parts are assembled to give rise to a central opening. The assembled full or partial length parts and/or modules may be assembled by inter-weaving them in various states, from a collapsed state, to a partially expanded state, to an expanded state.

Further, elements may be connected or attached by solvent or thermal bonding, or by mechanical attachment. If bonding, preferred methods of bonding comprise the use of ultrasonic radiofrequency or other thermal methods, and by solvents or adhesives or ultraviolet curing processes or photoreactive processes. The elements may be rolled by thermal forming, cold forming, solvent weakening forming and evaporation, or by preforming parts before linking.

Another method of manufacture allows for assembly of the stent components that have been cut out and assembled into flat series of radial elements. The linkage elements between longitudinally adjacent series of radial elements may be connected (e.g., by welding, inter-weaving frame elements, etc.), the flat sheets of material are rolled to form a tubular member. Coupling arms from floating coupling elements and end portions may be joined (e.g., by welding) to maintain the tubular shape. In embodiments that do not include coupling elements, the end portions of the top and bottom radial elements in a series may be joined. Alternatively, where sliding is desired throughout the entire circumference, a sliding and locking articulation can be made between the end portion of the top radial element and the rib(s)/rails of the bottom radial element (e.g., by tack-welding, heat-staking or snap-together). Similarly, a corresponding articulation can be made between the end portion of the bottom radial element and the rib(s)/rails of the top radial element.

Rolling of the flat series of module(s) to form a tubular member can be accomplished by any means known in the art, including rolling between two plates, which are each padded on the side in contact with the stent elements. One plate is held immobile and the other can move laterally with respect to the other. Thus, the stent elements sandwiched between the plates may be rolled about a mandrel by the movement of the plates relative to one another. Alternatively, 3-way spindle methods known in the art may also be used to roll the tubular member. Other rolling methods that may be used in accordance with the present invention include those used for “jelly-roll” designs, as disclosed for example, in U.S. Pat. Nos. 5,421,955, 5,441,515, 5,618,299, 5,443,500, 5,649,977, 5,643,314 and 5,735,872; the disclosures of which are incorporated herein in their entireties by reference thereto.

The construction of the slide-and-lock stents in these fashions provides a great deal of benefit over the prior art. The construction of the locking mechanism is largely material-independent. This allows the structure of the stent to comprise high strength materials, not possible with designs that require deformation of the material to complete the locking mechanism. The incorporation of these materials will allow the thickness required of the material to decrease, while retaining the strength characteristics of thicker stents. In preferred embodiments, the frequency of catches, stops or teeth present on selected circumferential elements prevents unnecessary recoil of the stent subsequent to expansion.

Radiopacity

Traditional methods for adding radiopacity to a medical product include the use of metal bands, inserts and/or markers, electrochemical deposition (i.e., electroplating), or coatings. The addition of radiopacifiers (i.e., radiopaque materials) to facilitate tracking and positioning of the stent could be accommodated by adding such an element in any fabrication method, by absorbing into or spraying onto the surface of part or all of the device. The degree of radiopacity contrast can be altered by element content.

For plastics and coatings, radiopacity may be imparted by use of monomers or polymers comprising iodine or other radiopaque elements, i.e., inherently radiopaque materials. Common radiopaque materials include barium sulfate, bismuth subcarbonate, and zirconium dioxide. Other radiopaque elements include: cadmium, tungsten, gold, tantalum, bismuth, platinum, iridium, and rhodium. In one preferred embodiment, a halogen such as iodine and/or bromine may be employed for its radiopacity and antimicrobial properties.

Multi-Material Vascular Prosthesis

In still other alternative embodiments, various materials (e.g., metals, polymers, ceramics, and therapeutic agents) may be used to fabricate stent embodiments. The embodiments may comprise: 1) differentially layered materials (through the vertical or radial axis) to create a stack of materials (materials may be stacked in any configuration, e.g., parallel, staggered, etc.); 2) spatially localized materials which may vary along the long axis and/or thickness of the stent body; 3) materials that are mixed or fused to create a composite stent body; 4) embodiments whereby a material is laminated (or coated) on the surface of the stent body (see Stent Surface Coatings with Functional Properties as well as see Therapeutic Agents Delivered by Stents); and, 5) stents comprised of 2 or more parts where at least one part is materially distinct from a second part, or any combination thereof.

The fashioning of a slide-and-lock multi-material stent can have between two or more materials. Thickness of each material may vary relative to other materials. This approach as needed or desired allows an overall structural member to be built with each material having one or more functions contributing towards enabling prosthesis function which includes, but is not limited to: 1) enabling mechanical properties for stent performance as defined by ultimate tensile strength, yield strength, Young's modulus, elongation at yield, elongation at break, and Poisson's ratio; 2) enabling the thickness of the substrate, geometrical shape (e.g., bifurcated, variable surface coverage); 3) enabling chemical properties of the material that bear relevance to the materials performance and physical state such as rate of degradation and resorption (which may impact therapeutic delivery), glass transition temperature, melting temperature, molecular weight; 4) enabling radiopacity or other forms of visibility and detection; 5) enabling radiation emission; 6) enabling delivery of a therapeutic agent (see Therapeutic Agents Delivered by Stents); and 7) enabling stent retention and/or other functional properties (see Stent Surface Coatings with Functional Properties).

In some embodiments, the materials may comprise load-bearing properties, elastomeric properties, mechanical strength that is specific to a direction or orientation e.g., parallel to another material and/or to the long axis of the stent, or perpendicular or uniform strength to another material and/or stent. The materials may comprise stiffeners, such as the following, boron or carbon fibers, pyrolytic carbon. Further, stents may be comprised of at least one re-enforcement such a fibers, nanoparticles or the like.

In another preferred mode of the invention, the stent is made, at least in part, from a polymeric material, which may be degradable. The motivation for using a degradable stent is that the mechanical support of a stent may only be necessary for several weeks. In some embodiments, bioresorbable materials with varying rates of resorption may be employed. For additional information, see U.S. patent application Ser. Nos. 10/952,202 and 60/601,526, which are incorporated by reference herein. Degradable polymeric stent materials may be particularly useful if it also controls restenosis and thrombosis by delivering pharmacologic agents. Degradable materials are well suited for therapeutic delivery (see Therapeutic Agents Delivered by S tents).

In some embodiments, the materials may comprise or contain any class of degradable polymer as previously defined. Along with variation in the time of degradation and/or resorption the degradable polymer may have other qualities that are desirable. For example, in some embodiments the materials may comprise or contain any example of natural polymers (biopolymers) and/or those that degrade by hydrolytic and/or enzymatic action. In some embodiments, the material may comprise or contain any example of hydrogels that may or may not be thermally reversible hydrogels, or any example of a light or energy curable material, or magnetically stimulateable (responding) material. Each of these responses may provide for a specific functionality.

In some embodiments, the materials may comprise or be made from or with constituents which has some radiopaque material alternatively, a clinically visible material which is visible by x-ray, fluoroscopy, ultrasound, MRI, or Imatron Electron Beam Tomography (EBT).

In some embodiments, one or more of the materials may emit predetermined or prescribed levels of therapeutic radiation. In one embodiment, the material can be charged with beta radiation. In another embodiment, the material can be charged with Gamma radiation. In yet another embodiment, the material can be charged with a combination of both Beta and Gamma radiation. Stent radioisotopes that may be used include, but are not limited to, 103Pd and 32P (phosphorus-32) and two neutron-activated examples, 65Cu and 87Rb2O, (90)Sr, tungsten-188 (188).

In some embodiments, one or more of the materials may comprise or contain a therapeutic agent. The therapeutic agents may have unique, delivery kinetics, mode of action, dose, half-life, purpose, et cetera. In some embodiments, one or more of the materials comprise an agent which provides a mode and site of action for therapy for example by a mode of action in the extracellular space, cell membrane, cytoplasm, nucleus and/or other intracellular organelle. Additionally an agent that serves as a chemoattractant for specific cell types to influence tissue formation and cellular responses for example host-biomaterial interactions, including anti-cancer effects. In some embodiments, one or more of the materials deliver cells in any form or state of development or origin. These could for example be encapsulated in a degradable microsphere, or mixed directly with polymer, or hydrogel and serve as vehicle for pharmaceutical delivery. Living cells could be used to continuously deliver pharmaceutical type molecules, for instance, cytokines and growth factors. Nonliving cells may serve as a limited release system. For additional concepts of therapeutic delivery, see the section entitled: Therapeutic Agents Delivered by Stents.

Therapeutic Agents Delivered by Stents

In another preferred variation, the stent further comprises an amount of a therapeutic agent (as previously defined for a pharmaceutical agent and/or a biologic agent) sufficient to exert a selected therapeutic effect. In some preferred embodiments of the stent (e.g., polymer stents and multi-material stents) the therapeutic agent is contained within the stent as the agent is blended with the polymer or admixed by other means known to those skilled in the art. In other preferred embodiments of the stent, the therapeutic agent is delivered from a polymer coating on the stent surface. In some preferred embodiments of the stent a therapeutic agent is localized in or around a specific structural aspect of the device.

In another preferred variation the therapeutic agent is delivered by means of a non-polymer coating. In other preferred embodiments of the stent, the therapeutic agent is delivered from at least one region or one surface of the stent. The therapeutic can be chemically bonded to the polymer or carrier used for delivery of the therapeutic from at least one portion of the stent and/or the therapeutic can be chemically bonded to the polymer that comprises at least one portion of the stent body. In one preferred embodiment, more than one therapeutic agent may be delivered.

The amount of the therapeutic agent is preferably sufficient to inhibit restenosis or thrombosis or to affect some other state of the stented tissue, for instance, heal a vulnerable plaque, and/or prevent rupture or stimulate endothelialization or limit other cell types from proliferating and from producing and depositing extracellular matrix molecules. The agent(s) may be selected from the group consisting of antiproliferative agents, anti-inflammatory, anti-matrix metalloproteinase, and lipid lowering, cholesterol modifying, anti-thrombotic and antiplatelet agents, in accordance with preferred embodiments of the present invention. Some of these preferred anti-proliferative agents that improve vascular patency include without limitation paclitaxel, Rapamycin, ABT-578, everolimus, dexamethasone, nitric oxide modulating molecules for endothelial function, tacrolimus, estradiol, mycophenolic acid, C6-ceramide, actinomycin-D and epothilones, and derivatives and analogs of each.

Some of these preferred agents act as an antiplatelet agent, antithrombin agent, compounds to address other pathologic events and/or vascular diseases. Various therapeutic agents may be classified in terms of their sites of action in the host: agents that exert their actions extracellularly or at specific membrane receptor sites, those that act on the plasma membrane, within the cytoplasm, and/or the nucleus.

In addition to the aforementioned, therapeutic agents may include other pharmaceutical and/or biologic agents intended for purposes of treating body lumens other than arteries and/or veins). Therapeutic agents may be specific for treating nonvascular body lumens such as digestive lumens (e.g., gastrointestinal, duodenum and esophagus, biliary ducts), respiratory lumens (e.g., tracheal and bronchial), and urinary lumens (e.g., urethra). Additionally such embodiments may be useful in lumens of other body systems such as the reproductive, endocrine, hematopoietic and/or the integumentary, musculoskeletal/orthopedic and nervous systems (including auditory and ophthalmic applications); and finally, stent embodiments with therapeutic agents may be useful for expanding an obstructed lumen and for inducing an obstruction (e.g., as in the case of aneurysms).

Therapeutic release may occur by controlled release mechanisms, diffusion, interaction with another agent(s) delivered by intravenous injection, aerosolization, or orally. Release may also occur by application of a magnetic field, an electrical field, or use of ultrasound.

Stent Surface Coatings with Functional Properties

In addition to stents that may deliver a therapeutic agent, for instance delivery of a biological polymer on the stent such as a repellant phosphorylcholine, the stent may be coated with other bioresorbable polymers predetermined to promote biological responses in the body lumen desired for certain clinical effectiveness. Further the coating may be used to mask (temporarily or permanently) the surface properties of the polymer used to comprise the stent embodiment. The coating may be selected from the broad class of any biocompatible bioresorbable polymer which may include any one or combination of halogenated and/or non-halogenated which may or may not comprise any poly(alkylene glycol). These polymers may include compositional variations including homopolymers and heteropolymers, stereoisomers and/or a blend of such polymers. These polymers may include for example, but are not limited to, polycarbonates, polyarylates, poly(ester amides), poly(amide carbonates), trimethylene carbonate, polycaprolactone, polydioxane, polyhydroxybutyrate, poly-hydroxyvalerate, polyglycolide, polylactides and stereoisomers and copolymers thereof, such as glycolide/lactide copolymers. In a preferred embodiment, the stent is coated with a polymer that exhibits a negative charge that repels the negatively charged red blood cells' outer membranes thereby reducing the risk of clot formation. In another preferred embodiment, the stent is coated with a polymer that exhibits an affinity for cells, (e.g., endothelial cells) to promote healing. In yet another preferred embodiment, the stent is coated with a polymer that repels the attachment and/or proliferation of specific cells, for instance arterial fibroblasts and/or smooth muscle cells in order to lessen restenosis and/or inflammatory cells such as macrophages.

Described above are the stents of the present invention that may be modified with a coating to achieve functional properties that support biological responses. Such coatings or compositions of material with a therapeutic agent may be formed on stents or applied in the process of making a stent body via techniques such as dipping, spray coating, cross-linking combinations thereof, and the like. Such coatings or compositions of material may also serve purpose other than delivering a therapeutic, such as to enhance stent retention on a balloon when the coating is placed intraluminally on the stent body and/or placed over the entire device after the stent is mounted on the balloon system to keep the stent in a collapsed formation. Other purposes can be envisioned by those skilled in the art when using any polymer material.

In one aspect of the invention, a stent would have a coating applied that has specific mechanical properties. The properties may include inter alia thickness, tensile strength, glass transition temperature, and surface finish. The coating is preferably applied. prior to final crimping or application of the stent to the catheter. The stent may then be applied to the catheter and the system may have either heat or pressure or both applied in a compressive manner. In the process, the coating may form frangible bonds with both the catheter and the other stent surfaces. The bonds would enable a reliable method of creating stent retention and of holding the stent crossing profile over time. The bonds would break upon the balloon deployment pressures. The coating would be a lower Tg than the substrate to ensure no changes in the substrate.

Stent Deployment

First, a catheter is provided wherein an expandable member, preferably an inflatable balloon, such as an angioplasty balloon, is provided along a distal end portion. One example of a balloon catheter for use with a stent is described in U.S. Pat. No. 4,733,665 to Palmaz, which is incorporated by reference herein. A stent on a catheter is commonly collectively referred to as a stent system. Catheters include but are not limited to over-the-wire catheters, coaxial rapid-exchange designs and the Medtronic Zipper Technology that is a new delivery platform. Such catheters may include for instance those described in Bonzel U.S. Pat. Nos. 4,762,129 and 5,232,445 and by Yock U.S. Pat. Nos. 4,748,982; 5,496,346; 5,626,600; 5,040,548; 5,061,273; 5,350,395; 5,451,233 and 5,749,888. Additionally, catheters may include for instance those as described in U.S. Pat. Nos. 4,762,129; 5,092,877; 5,108,416; 5,197,978; 5,232,445; 5,300,085; 5,445,646; 5,496,275; 5,545,135; 5,545,138; 5,549,556; 5,755,708; 5,769,868; 5,800,393; 5,836,965; 5,989,280; 6,019,785; 6,036,715; 5,242,399; 5,158,548; and 6,007,545. The disclosures of the above-cited patents are incorporated herein in their entirety by reference thereto.

Catheters may be specialized with highly compliant polymers and for various purposes such as to produce an ultrasound effect, electric field, magnetic field, light and/or temperature effect. Heating catheters may include for example those described in U.S. Pat. Nos. 5,151,100, 5,230,349; 6,447,508; and 6,562,021 as well as WO9014046A1. Infrared light emitting catheters may include for example those described in U.S. Pat. Nos. 5,910,816 and 5,423,321. The disclosures of the above-cited patents and patent publications are incorporated herein in their entirety by reference thereto.

An expandable member, such as an inflatable balloon, is preferably used to deploy the stent at the treatment site. As the balloon is expanded, the radial force of the balloon overcomes the initial resistance of the constraining mechanism, thereby allowing the stent to expand. As the balloon is inflated, the radial elements slide with respect to each other along the surface of the balloon until the stent has been expanded to a desired diameter.

The stent of embodiments of the invention are adapted for deployment using conventional methods known in the art and employing percutaneous transluminal catheter devices. This includes deployment in a body lumen by means of a balloon expandable design whereby expansion is driven by the balloon expanding. Alternatively, the stent may be mounted onto a catheter that holds the stent as it is delivered through the body lumen and then releases the stent and allows it to self-expand into contact with the body lumen. The restraining means may comprise a removable sheath and/or a mechanical aspect of the stent design.

Some embodiments of the invention may be useful in coronary arteries, carotid arteries, vascular aneurysms (when covered with a sheath), and peripheral arteries and veins (e.g., renal, iliac, femoral, popliteal, subclavian, aorta, intercranial, etc.). Other nonvascular applications include gastrointestinal, duodenum, biliary ducts, esophagus, urethra, reproductive tracts, trachea, and respiratory (e.g., bronchial) ducts. These applications may or may not require a sheath covering the stent.

It is desirable to have the stent radially expand in a uniform manner. Alternatively, the expanded diameter may be variable and determined by the internal diameter and anatomy of the body passageway to be treated. Accordingly, uniform and variable expansion of the stent that is controlled during deployment is not likely to cause a rupture of the body passageway. Furthermore, the stent will resist recoil because the locking means resist sliding of the mating elements. Thus, the expanded intraluminal stent will continue to exert radial pressure outward against the wall of the body passageway and will therefore, not migrate away from the desired location.

From the foregoing description, it will be appreciated that a novel approach for expanding a lumen has been disclosed. While the components, techniques and aspects of the invention have been described with a certain degree of particularity, it is manifest that many changes may be made in the specific designs, constructions and methodology herein above described without departing from the spirit and scope of this disclosure.

While a number of preferred embodiments of the invention and variations thereof have been described in detail, other modifications and methods of using and medical applications for the same will be apparent to those of skill in the art. Accordingly, it should be understood that various applications, modifications, materials, and substitutions may be made of equivalents without departing from the spirit of the invention or the scope of the claims.

Various modifications and applications of the invention may occur to those who are skilled in the art, without departing from the true spirit or scope of the invention. It should be understood that the invention is not limited to the embodiments set forth herein for purposes of exemplification, but is to be defined only by a fair reading of the appended claims, including the full range of equivalency to which each element thereof is entitled.

References

Some of the references cited herein are listed below, the entirety of each one of which is hereby incorporated by reference herein:

-   -   Charles R, Sandirasegarane L, Yun J, Bourbon N, Wilson R,         Rothstein R P, et al. Ceramide-Coated Balloon Catheters Limit         Neointimal Hyperplasia after Stretch Injury in Carotid Arteries.         Circ Res 2000; 87(4):282-288.     -   Coroneos E, Martinez M, McKenna S, Kester M. Differential         regulation of sphingomyelinase and ceramidase activities by         growth factors and cytokines. Implications for cellular         proliferation and differentiation. J Biol Chem 1995;         270(40):23305-9.     -   Coroneos E, Wang Y, Panuska J R, Templeton D J, Kester M.         Sphingolipid metabolites differentially regulate extracellular         signal-regulated kinase and stress-activated protein kinase         cascades. Biochem J 1996; 316(Pt 1):13-7.     -   Jacobs L S, Kester M. Sphingolipids as mediators of effects of         platelet-derived growth factor in vascular smooth muscle cells.         Am J Physiol 1993; 265(3 Pt 1):C740-7.     -   Tanguay J F, Zidar J P, Phillips H R, 3rd, Stack R S. Current         status of biodegradable stents. Cardiol Clin 1994;         12(4):699-713.     -   Nikol S, Huehns T Y, Hofling B. Molecular biology and         post-angioplasty restenosis. Atherosclerosis 1996;         123(1-2):17-31.     -   Biomaterials Science: An Introduction to Materials in Medicine         (29 Jul. 2004) Ratner, Hoffman, Schoen, and Lemons. 

What is claimed is:
 1. A stent being expandable from an unexpanded state to an expanded state, the stent comprising a tubular member having a longitudinal axis, the tubular member comprising: a first linkage section comprising a housing, the housing comprising a chamber and at least one engagement opening in communication with the chamber; and a second linkage section comprising an elongate body and a plurality of arm members, the elongate body being unitary with the arm members, the arm members extending in alternating circumferential directions from the elongate body, each of the arm members being longitudinally offset from all other arm members along the elongate body, at least one of the arm members configured to engage the at least one engagement opening of the housing of the first linkage section, wherein a distal end of the at least one of the arm members configured to engage the at least one engagement opening is housed within the chamber of the housing of the first linkage section when the stent is in the unexpanded and expanded states, the at least one of the arm members configured to engage the at least one engagement opening being configured to allow one-way slidable movement of the first linkage section relative to the elongate body during expansion of the stent from the unexpanded state to the expanded state.
 2. The stent of claim 1, wherein: the at least one engagement opening of the housing comprises a pair of engagement openings, the second linkage section comprises a pair of arm members, the pair of arm members comprising a first arm member and a second arm member, the pair of arm members being configured to engage with the pair of engagement openings of the housing of the first linkage section, and wherein the housing comprises another opening spaced longitudinally intermediate the pair of engagement openings for receiving a third arm member, wherein the third arm member is disposed between the pair of arm members within the housing of the first linkage section when the stent is in the unexpanded state.
 3. The stent of claim 1, wherein the at least one engagement opening extends circumferentially.
 4. The stent of claim 1, wherein the at least one of the arm members configured to engage the at least one engagement opening of the second linkage section defines a circumferential length and the chamber of the housing of the first linkage section defines a chamber length, wherein the circumferential length of the at least one of the arm members configured to engage the at least one engagement opening is approximately equal to the chamber length.
 5. The stent of claim 4, wherein the at least one of the arm members configured to engage the at least one engagement opening is received entirely within the chamber when the stent is in the unexpanded state.
 6. The stent of claim 1, wherein the at least one engagement opening of the first linkage section comprises first and second engagement openings, the first engagement opening and the second engagement opening extending circumferentially such that the housing can receive opposing arm members within the chamber thereof.
 7. The stent of claim 1, wherein the at least one of the arm members configured to engage the at least one engagement opening comprises a plurality of teeth, and wherein the chamber is configured to receive the each of the teeth in the unexpanded state, and wherein each of the teeth being disposed outside the chamber in the expanded state.
 8. The stent of claim 1, wherein the at least one of the arm members configured to engage the at least one engagement opening comprises an end stop configured to limit the maximum stent expansion of the first linkage section relative to the second linkage section.
 9. The stent of claim 1, wherein the housing further comprises a clearence elements configured to inhibit initial expansion of the stent.
 10. The stent of claim 9, wherein each clearance element engages with the distal end of the at least one of the arm members when the stent is in the unexpanded state.
 11. The stent of claim 1, wherein the chamber is at least partly radially enclosed.
 12. The stent of claim 1, wherein the housing further comprises a shielding component extending longitudinally across the chamber and being configured to align the at least one of the arm members configured to engage the at least one engagement opening in the chamber, the shielding being radially offset from the chamber.
 13. The stent of claim 1, wherein the plurality of arm members comprises a first plurality that circumferentially extends from a first side of the second linkage section and a second plurality that circumferentially extends from a second side of the second linkage section, the first and second pluralities comprising different numbers of arm members.
 14. The stent of claim 1, wherein the at least one engagement opening of the first linkage section comprises a first number of engagement openings disposed on a first side of the housing and a second number of engagement openings disposed on a second side of the housing, wherein the first and second numbers of engagement openings are different.
 15. The stent of claim 1, wherein the elongate body and the plurality of arm members are fixedly connected.
 16. A stent being expandable from a fully unexpanded state to an expanded state, the stent comprising a tubular member having a longitudinal axis, the tubular member comprising: a longitudinally extending first linkage section comprising a housing, the housing comprising a chamber and a plurality of longitudinally spaced engagement openings in communication with the chamber; and a longitudinally extending second linkage section comprising an elongate body and a plurality of arm members being fixed relative to the elongate body and each defining a circumferential length, the arm members being longitudinally spaced and extending from first and second opposing sides of the elongate body in opposing circumferential directions, the arm members extending from the first opposing side being configured to engage with the housing of the first linkage section and to have substantially the entire circumferential length thereof received within the chamber of the housing when the stent is in the fully unexpanded state, wherein the arm members are configured to allow one-way slidable movement of the first linkage section relative to the second linkage section during expansion of the stent from the fully unexpanded state to the expanded state.
 17. The stent of claim 16, wherein the arm members of the second linkage section extend alternatingly from the first and second opposing sides of the elongate body.
 18. The stent of claim 16, wherein the second linkage section comprises a pair of arm members configured to engage with a pair of corresponding engagement openings of the housing of the first linkage section.
 19. The stent of claim 18, wherein the housing comprises another opening spaced longitudinally intermediate the pair of corresponding openings for receiving a third arm member, wherein the third arm member is disposed between the pair of arm members within the housing of the first linkage section when the stent is in the fully unexpanded state.
 20. The stent of claim 16, wherein the chamber defines a chamber length and the circumferential length of the arm members is approximately equal to the chamber length.
 21. The stent of claim 16, wherein the chamber is at least partly radially enclosed.
 22. The stent of claim 16, wherein the housing further comprises a shielding component extending longitudinally across the chamber and being configured to maintain an alignment of the arm members that are received in the chamber.
 23. The stent of claim 16, wherein the first opposing side of the elongate body has a different number of arm members extending therefrom than the second opposing side of the elongate body.
 24. The stent of claim 16, wherein the plurality of longitudinally spaced engagement openings comprises a first set disposed on a first side of the housing and a second set disposed on a second side of the housing, wherein the number of engagement openings in the first set is different than the number of engagement openings in the second set.
 25. The stent of claim 16, wherein the housing further comprises a plurality of longitudinally extending walls that are offset a circumferential distance from each other, the circumferential distance being substantially unchanged as the stent expands from the fully unexpanded state to the expanded state.
 26. A stent being expandable from an unexpanded state to an expanded state, the stent comprising a tubular member having a longitudinal axis, the tubular member comprising: a first linkage section comprising a first structural element, the first structural element comprising a first side and a second side, the first side and the second side each comprising at least one engagement opening, the at least one engagement opening of the first side being spaced at a substantially constant circumferential offset from the at least one engagement opening of the second side, the substantially constant circumferential offset remaining substantially constant as the stent expands from the unexpanded state to the expanded state; a second linkage section comprising a second elongate body and a plurality of second arm members being fixed relative to the second elongate body, the second arm members being longitudinally spaced and extending from opposing sides of the second elongate body in opposing circumferential directions, at least some of the second arm members being configured to slidably engage with at least one of the at least one engagement opening on the first side of the first structural element; and a third linkage section comprising a third elongate body and a plurality of third arm members, the third arm members being longitudinally spaced and extending from opposing sides of the third elongate body in opposing circumferential directions, at least some of the third arm members being configured to slidably engage with at least one of the at least one engagement opening on the second side of the first structural element, wherein the second linkage section and the third linkage section are configured to provide one-way separation relative to each other and the first linkage section during expansion of the stent from the unexpanded state to the expanded state.
 27. The stent of claim 26, wherein the first structural element comprises a housing that defines a chamber, the at least one engagement opening of the first side and the at least one engagement opening of the second side being in communication with the chamber, wherein at least one of the first and second sides includes a plurality of engagement openings configured to slidably receive at least one second arm member and at least one third arm member such that the at least one second arm member and the at least one third arm member are at least partially disposed within the chamber of the housing.
 28. The stent of claim 27, wherein the chamber is at least partly radially enclosed.
 29. The stent of claim 27, wherein the housing further comprises a shielding component extending longitudinally across the chamber and being configured to maintain an alignment of the second arm and third arm members.
 30. The stent of claim 26, wherein the first linkage section comprises a plurality of first structural elements for interconnecting with second arm members and third arm members.
 31. The stent of claim 30, wherein the plurality of first structural elements are interconnected to each other with a longitudinal backbone.
 32. The stent of claim 26, wherein the second arm members of the second linkage section extend alternatingly from the opposing sides of the second elongate body, and the third arm members of the third linkage section extend alternatingly from the opposing sides of the third elongate body.
 33. The stent of claim 26, wherein the first side of the first structural element has a different number of engagement openings than the second side of the first structural element.
 34. The stent of claim 26, wherein the second and third linkage sections are configured to circumferentially move relative to the first linkage section and relative to each other during expansion of the stent. 